Cytokine-armed dendritic cell progenitors for antigen-agnostic cancer immunotherapy

Dendritic cells (DCs) are antigen-presenting myeloid cells that regulate T cell activation, trafficking and function. Monocyte-derived DCs pulsed with tumor antigens have been tested extensively for therapeutic vaccination in cancer, with mixed clinical results. Here, we present a cell-therapy platform based on mouse or human DC progenitors (DCPs) engineered to produce two immunostimulatory cytokines, IL-12 and FLT3L. Cytokine-armed DCPs differentiated into conventional type-I DCs (cDC1) and suppressed tumor growth, including melanoma and autochthonous liver models, without the need for antigen loading or myeloablative host conditioning. Tumor response involved synergy between IL-12 and FLT3L and was associated with natural killer and T cell infiltration and activation, M1-like macrophage programming and ischemic tumor necrosis. Antitumor immunity was dependent on endogenous cDC1 expansion and interferon-γ signaling but did not require CD8+ T cell cytotoxicity. Cytokine-armed DCPs synergized effectively with anti-GD2 chimeric-antigen receptor (CAR) T cells in eradicating intracranial gliomas in mice, illustrating their potential in combination therapies.

Intestinal B cells license metabolic T-cell activation in NASH microbiota/antigen-independently and contribute to fibrosis by IgA-FcR signalling

BACKGROUND & AIMS

The progression of non-alcoholic steatohepatitis (NASH) to fibrosis and hepatocellular carcinoma (HCC) is aggravated by auto-aggressive T cells. The gut-liver axis contributes to NASH, but the mechanisms involved and the consequences for NASH-induced fibrosis and liver cancer remain unknown. We investigated the role of gastrointestinal B cells in the development of NASH, fibrosis and NASH-induced HCC.

METHODS

C57BL/6J wild-type (WT), B cell-deficient and different immunoglobulin-deficient or transgenic mice were fed distinct NASH-inducing diets or standard chow for 6 or 12 months, whereafter NASH, fibrosis, and NASH-induced HCC were assessed and analysed. Specific pathogen-free/germ-free WT and μMT mice (containing B cells only in the gastrointestinal tract) were fed a choline-deficient high-fat diet, and treated with an anti-CD20 antibody, whereafter NASH and fibrosis were assessed. Tissue biopsy samples from patients with simple steatosis, NASH and cirrhosis were analysed to correlate the secretion of immunoglobulins to clinicopathological features. Flow cytometry, immunohistochemistry and single-cell RNA-sequencing analysis were performed in liver and gastrointestinal tissue to characterise immune cells in mice and humans.

RESULTS

Activated intestinal B cells were increased in mouse and human NASH samples and licensed metabolic T-cell activation to induce NASH independently of antigen specificity and gut microbiota. Genetic or therapeutic depletion of systemic or gastrointestinal B cells prevented or reverted NASH and liver fibrosis. IgA secretion was necessary for fibrosis induction by activating CD11b+CCR2+F4/80+CD11c-FCGR1+ hepatic myeloid cells through an IgA-FcR signalling axis. Similarly, patients with NASH had increased numbers of activated intestinal B cells; additionally, we observed a positive correlation between IgA levels and activated FcRg+ hepatic myeloid cells, as well the extent of liver fibrosis.

CONCLUSIONS

Intestinal B cells and the IgA-FcR signalling axis represent potential therapeutic targets for the treatment of NASH.

IMPACT AND IMPLICATIONS

There is currently no effective treatment for non-alcoholic steatohepatitis (NASH), which is associated with a substantial healthcare burden and is a growing risk factor for hepatocellular carcinoma (HCC). We have previously shown that NASH is an auto-aggressive condition aggravated, amongst others, by T cells. Therefore, we hypothesized that B cells might have a role in disease induction and progression. Our present work highlights that B cells have a dual role in NASH pathogenesis, being implicated in the activation of auto-aggressive T cells and the development of fibrosis via activation of monocyte-derived macrophages by secreted immunoglobulins (e.g., IgA). Furthermore, we show that the absence of B cells prevented HCC development. B cell-intrinsic signalling pathways, secreted immunoglobulins, and interactions of B cells with other immune cells are potential targets for combinatorial NASH therapies against inflammation and fibrosis.

[Melanosis of the urinary bladder]

Melanosis of the bladder is rare. Only 10 cases have been described in the literature. We present the case of an 80-year-old woman with neurogenic lower urinary tract dysfunction due to spinal paralysis. During the diagnostic work-up which included cystoscopy, black spots in the bladder wall were observed. Histopathological evaluation revealed a benign suburothelial melanosis. Thus, with cystoscopic suspicion of a malignancy (melanoma), a biopsy is mandatory and regular cystoscopic follow-up is recommended.

[Psammomatous tenosynovialitis of hand and forearm - three new cases]

We report about three new observations of psammomatous tenosynovialitis on hand and forearm and performed a review of literature. To the best of our knowledge cases 7, 8 and 9 in the medical literature are now published.

Postoperative determination of the degree of carotid artery stenosis

This article describes the VascMorph 1a prototype software and reports first results obtained with postoperative determination of the degree of stenosis in the carotid artery.

[Recurrence of a tendon sheath tumor on the hand consisting of three morphological components]

We report of a benign, recurrent tendon sheath tumour. Histologically, three different morphological components were observed.

The pedunculopontine nucleus is related to visual hallucinations in Parkinson's disease: preliminary results of a voxel-based morphometry study

Visual hallucinations (VH) are common in Parkinson’s disease (PD) and lead to a poor quality of life. For a long time, dopaminergic therapy was considered to be the most important risk factor for the development of VH in PD. Recently, the cholinergic system, including the pedunculopontine nucleus (PPN), has been implicated in the pathophysiology of VH. The aim of the present study was to investigate grey matter density of the PPN region and one of its projection areas, the thalamus. Thirteen non-demented PD patients with VH were compared to 16 non-demented PD patients without VH, 13 demented PD patients (PDD) with VH and 11 patients with dementia with Lewy bodies (DLB). Isotropic 3-D T1-weighted MRI images (3T) were analysed using voxel-based morphometry (VBM) with the PPN region and thalamus as ROIs. PD and PDD patients with VH showed grey matter reductions of the PPN region and the thalamus compared to PD patients without VH. VH in PD(D) patients are associated with atrophy of the PPN region and its thalamic target area, suggesting that a cholinergic deficit may be involved in the development of VH in PD(D).

[Ascending aortic and pulmonary trunk aneurysms]

A case of two non-atherosclerotic aneurysms localised in the ascending aorta and in the pulmonary trunk is presented. Histopathologically, a severe granulomatous inflammation affecting the whole aneurysms wall was documented. To the best of our knowledge it is the second ever documented case of simultaneous occurrence of aneurysms in the aorta and the pulmonary artery.

Insufficient arteriovenous fistulae in hemodialysis patients

BACKGROUND

For an accurate assessment of structural changes in arteriovenous fistulae (AVF) a microscopic analysis is mandatory.

METHODS

25 insufficient AVF were analyzed with the light microscope using standard histological and immunohistochemical techniques.

RESULTS

In 7 patients (28%) atherosclerotic lesions as causes of AVF insufficiency were found. The other 18 patients (72%) had an inhomogeneous spectrum of nonatherosclerotic lesions, for instance intimal hyperplasia.

CONCLUSIONS

Histopathologic analysis of insufficient AVF helps clarify the underlying changes in the structure of the vessel wall.

Non-invasive evaluation of atherosclerosis with contrast enhanced 16 slice spiral computed tomography: results of ex vivo investigations

OBJECTIVE

To evaluate the diagnostic accuracy of 16 slice computed tomography (CT) in determining plaque morphology and composition in an experimental setting. The results were compared with histopathological analysis as the reference standard.

METHODS

Nine human popliteal arteries derived from amputations because of atherosclerotic disease were investigated with multislice spiral CT (MSCT). Atherosclerotic lesions were morphologically classified (completely or partially occlusive, concentric, eccentric), and tissue densities were determined within these plaques. In addition, vessel dimensions were quantitatively measured.

RESULTS

The results were compared with histological analysis. The concordance index kappa for morphological classification was 0.88. Plaque density (n = 51 lesions) was significantly different (p < 0.0001) between lipid rich, fibrotic, and calcified lesions (Stary stage III: n = 2, 58 (8) Hounsfield units (HU); Stary V: n = 11, 50 (21) HU; Stary VI: n = 14, 96 (42) HU; Stary VII: n = 6, 858 (263) HU; Stary VIII: n = 18, 126 (99) HU). The concordance index kappa for the classification of plaques based on density was 0.51. Vessel dimensions had a good correlation (r = 0.98).

CONCLUSIONS

16 slice CT was found to be a reliable non-invasive imaging technique for assessing atherosclerotic plaque morphology and composition. Although calcified lesions can be differentiated from non-calcified lesions, the diagnostic accuracy in further subclassifying non-calcified plaques as lipid rich and fibrotic is low, even under experimental conditions.

The microscopic transitional zone between elastic and muscular arteries

The microscopic transitional zone (TZ) is a segment of the arterial tree, where elastic-type wall architecture is relayed by one of muscular type. Since arterial TZ's are often sites of atherosclerotic and non-atherosclerotic lesions, this histologic anatomic substrate should be considered in the etiology and pathogenesis of vascular diseases. Herein, the topography and fine structure of TZ in renal arteries and carotid bifurcation (tripod) is described, based on randomly collected human autopsy specimens. The average length of the TZ was found to be 10 mm in the renal arteries. The TZ In the carotid tripod was localised only in the postbifurcational segments, where the length varied between 5 and more than 20 mm. In accordance with previous data from the literature, our results confirm a different ratio of scleroprotein components (elastin, collagen) and vascular smooth muscle cells (VSMC) in the microscopic TZ of arteries. Immunohistochemistry for lymphomonocytic antigens revealed no underlying inflammatory condition, especially no evidence of active cellular scavenging and an increased apoptotic rate of VSMC. We perceive the TZ as an arterial segment of reduced architectural compliance and, therefore, as a potential site of mechanotransductional failure leading to vascular diseases.

ABIN-2 forms a ternary complex with TPL-2 and NF-kappa B1 p105 and is essential for TPL-2 protein stability

NF-kappa B1 p105 forms a high-affinity, stoichiometric interaction with TPL-2, a MEK kinase essential for TLR4 activation of the ERK mitogen-activated protein kinase cascade in lipopolysaccharide (LPS)-stimulated macrophages. Interaction with p105 is required to maintain TPL-2 metabolic stability and also negatively regulates TPL-2 MEK kinase activity. Here, affinity purification identified A20-binding inhibitor of NF-kappa B 2 (ABIN-2) as a novel p105-associated protein. Cotransfection experiments demonstrated that ABIN-2 could interact with TPL-2 in addition to p105 but preferentially formed a ternary complex with both proteins. Consistently, in unstimulated bone marrow-derived macrophages (BMDMs), a substantial fraction of endogenous ABIN-2 was associated with both p105 and TPL-2. Although the majority of TPL-2 in these cells was complexed with ABIN-2, the pool of TPL-2 which could activate MEK after LPS stimulation was not, and LPS activation of TPL-2 was found to correlate with its release from ABIN-2. Depletion of ABIN-2 by RNA interference dramatically reduced steady-state levels of TPL-2 protein without affecting levels of TPL-2 mRNA or p105 protein. In addition, ABIN-2 increased the half-life of cotransfected TPL-2. Thus, optimal TPL-2 stability in vivo requires interaction with ABIN-2 as well as p105. Together, these data raise the possibility that ABIN-2 functions in the TLR4 signaling pathway which regulates TPL-2 activation.

Takayasu's arteritis secondary to myelodysplasia as a predictor of poor outcome: two case reports

We present two patients with myelodysplasia in association with Takayasu's arteritis (TA). In both patients intensive immunosuppressive treatment could not control the vascular inflammation. Subsequently both patients developed myelodysplasia, rapidly progressing to secondary acute myelogenous leukaemia. One patient had a peripheral blood stem cell transplant from a compatible sibling donor, but died of refractory leukaemia 5 months later. The other patient died of fungal sepsis. These are the first two patients reported to have TA associated with myelodysplasia/secondary leukaemia.

[Radiologic-histopathologic correlation of microcalcifications from 11g vacuum biopsy: analysis of 3196 core biopsies]

PURPOSE

To perform a statistical evaluation of microcalcifications (MC) from suspicious breast lesions detected by radiography and histopathology.

MATERIALS AND METHODS

Histological and radiological detection of calcifications were compared from 116 biopsies in 96 women. Lesions with identical description of calcifications detected in histopathology and radiography were considered concordant, patients with obvious discrepancies discordant. If histological and radiological groups of calcifications were identical in number but differed in location, the case was considered pseudo-concordant.

RESULTS

Histopathology classified 24 of 116 lesions as malignant and 92 as benign. A total of 3196 core biopsies were examined, 851 of these contained groups of calcifications or single calcifications. Both modalities detected 579 calcifications, with 169 exclusively detected by radiography and 103 exclusively by histopathology. In 35 cases (30 %) radiologic and pathologic results were concordant, in 6 cases pseudo-concordant (4 %) and in 75 cases (65 %) discordant. The case-based Kappa coefficient was - 0.09 (- 0.24 to 0.07). The 122 calcifications not detected by histopathology were few or single calcifications at the edge of the core that were probably lost during processing, 18 were possible artefacts. Six cores contained calcium oxalate, 3 contained milk of calcium. In 6 cases malignant disease was found after the first examination, hence the cores were not searched thoroughly for the missing calcifications. In the remaining 14 cases, no calcifications were found despite complete processing of the tissue. In 49 of 103 cases of radiologically undetected microcalcifications, the retrospect analysis showed dense tissue areas that probably contained the calcification. The remaining 54 cases contained calcifications, which were too small to be detected radiologically.

SUMMARY

Discordant results from pathological and radiological examinations of biopsies can mainly be explained by calcifications at the edge of the specimen lost during processing, which are therefore not detected in histopathology, and calcifications too small to be visualized radiologically.

Fibromuscular dysplasia of the renal artery responsible for renovascular hypertension: a histological presentation based on a series of 102 patients

Background: Fibromuscular dysplasia (FMD) is a rare non-atherosclerotic and non-inflammatory disease in the arterial system. The purpose of the study was a retrospective analysis of FMD in the renal artery. Patients and methods: A total number of 102 patients (mean age: 36.9 years) who suffered from renovascular hypertension underwent a surgical therapy. The operative specimens of the renal arteries were analysed with the lightmicroscop using histological and immunohistochemical methods. Results: 101 patients (99.02%) presented a medial FMD (extensive-medial subtype in 56 patients, 54.9%, subadventitial subtype in 29 patients, 28.4% and combined subtype in 16 patients, 15.7%). In 1 patient (0.98%) an adventitial FMD was found. We observed the following complications: true and dissecting aneurysms (75 patients, 74.5%), arterio-venous fistulae (2 patients, 1.96%) and chronic thrombosis (10 patients, 9.8%). Conclusions: With the progress in angioplasty, not all patients suffering from FMD undergo a primary surgical therapy and therefore this lesion is less seen in the daily work of the histopathologist.

Intrathoracic and intraabdominal locations of a cystic benign tumor: congenital etiology due to embryological diaphragm development?

A rare case of a benign cystic two-cavity tumor with intrathoracic and intraabdominal localisation is presented. The tumor's embryological etiology, embryological development of the diaphragm and the occurrence of embryonic tumors in general, are discussed. To our knowledge this is the first documented case of a benign two-cavity tumor in childhood and infancy.

Sebaceous glands in the uterine cervix: two new cases

The authors report on two new cases of sebaceous glands in the uterine cervix. This extremely rare histological observation was found on biopsy specimens of the uterine cervix because of unclear colposcopic findings and of recurrent CIN II. The etiology of this entity is discussed including a brief review of the medical literature.

CD40 regulates the processing of NF-kappaB2 p100 to p52

The nf-kb2 gene encodes the cytoplasmic NF-kappaB inhibitory protein p100 from which the active p52 NF-kappaB subunit is derived by proteasome-mediated proteolysis. Ligands which stimulate p100 processing to p52 have not been defined. Here, ligation of CD40 on transfected 293 cells is shown to trigger p52 production by stimulating p100 ubiquitylation and subsequent proteasome-mediated proteolysis. CD40-mediated p52 accumulation is dependent on de novo protein synthesis and triggers p52 translocation into the nucleus to generate active NF-kappaB dimers. Endogenous CD40 ligation on primary murine splenic B cells also stimulates p100 processing, which results in the delayed nuclear translocation of p52-RelB dimers. In both 293 cells and primary splenic B cells, the ability of CD40 to trigger p100 processing requires functional NF-kappaB-inducing kinase (NIK). In contrast, NIK activity is not required for CD40 to stimulate the degradation of IkappaBalpha in either cell type. The regulation of p100 processing by CD40 is likely to be important for the transcriptional regulation of CD40 target genes in adaptive immune responses.

Urinary bladder biopsies in spinal cord injured patients

STUDY DESIGN

A series of 94 urinary bladder biopsies in spinal cord injured (SCI) patients were histopathologically and statistically analysed.

OBJECTIVES

The following hypotheses were examined: (1) The number of clinical bladder infections per year in each patient does not influence the histopathological type of inflammation of the urinary bladder; (2) The duration of the spinal cord lesion does not have a strong effect on the type of inflammation; (3) The different neurological levels (upper and lower motor neuron lesions) do not relate to a specific histopathology.

SETTINGS

All patients received their treatment at the Swiss Paraplegic Centre in Nottwil, near Lucerne (Switzerland).

METHODS

The samples were taken from the bladder fundus during endoscopic urologic operations. Histopathological standard procedures were carried out. Statistical analysis including Kruskal-Wallis and Chi-square tests were performed.

RESULTS

Histopathological analysis showed abnormal alterations of the urinary bladder mucosa in 86 SCI-patients: (91.5%). 63 cases (67.0%) showed a chronic type and 23 cases (24.5%) showed a subacute type of inflammation. A normal urinary bladder was found in eight cases (8.5%). The three hypotheses were statistically not rejected.

CONCLUSION

Results demonstrated no correlation between the number of bladder infections per year, the period since injury, the neurologic level of the spinal cord lesion and the histopathology of the urinary bladder mucosa.

Arterial calcifications: morphological aspects and their pathological implications

Morphological aspects of calcifications are identical whatever their site in the arterial layers: fine granular deposits, plates, rings. Occurrence of complications: fibrosis with foreign body type granuloma, thrombosis, and embolism mainly depend on the site and the amount of calcification. Clinicians should be aware of these complications when performing angioplasty.

Direct phosphorylation of NF-kappaB1 p105 by the IkappaB kinase complex on serine 927 is essential for signal-induced p105 proteolysis

The p105 precursor protein of NF-kappaB1 acts as an NF-kappaB inhibitory protein, retaining associated Rel subunits in the cytoplasm of unstimulated cells. Tumor necrosis factor alpha (TNFalpha) and interleukin-1alpha (IL-1alpha) stimulate p105 degradation, releasing associated Rel subunits to translocate into the nucleus. By using knockout embryonic fibroblasts, it was first established that the IkappaB kinase (IKK) complex is essential for these pro-inflammatory cytokines to trigger efficiently p105 degradation. The p105 PEST domain contains a motif (Asp-Ser(927)-Gly-Val-Glu-Thr), related to the IKK target sequence in IkappaBalpha, which is conserved between human, mouse, rat, and chicken p105. Analysis of a panel of human p105 mutants in which serine/threonine residues within and adjacent to this motif were individually changed to alanine established that only serine 927 is essential for p105 proteolysis triggered by IKK2 overexpression. This residue is also required for TNFalpha and IL-1alpha to stimulate p105 degradation. By using a specific anti-phosphopeptide antibody, it was confirmed that IKK2 overexpression induces serine 927 phosphorylation of co-transfected p105 and that endogenous p105 is also rapidly phosphorylated on this residue after TNFalpha or IL-1alpha stimulation. In vitro kinase assays with purified proteins demonstrated that both IKK1 and IKK2 can directly phosphorylate p105 on serine 927. Together these experiments indicate that the IKK complex regulates the signal-induced proteolysis of NF-kappaB1 p105 by direct phosphorylation of serine 927 in its PEST domain.

Variable extension of the transitional zone in the medial structure of carotid artery tripod

BACKGROUND

The goal of our study was to demonstrate the extension of the transitional zone (TZ) between elastic and muscular medial structure in carotid artery tripod.

PATIENTS AND METHODS

A histologic study of 56 probes from 8 carotid artery tripods was performed. The probes were obtained from autopsies of 4 adults (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 different topographic sites.

RESULTS

At each level of the CCA (at 1 cm and 2 cm proximal to the bifurcation as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view field (200 x magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arterial type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) muscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sections (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions have prevented the assessment of the arterial type in 4 probes (7.1%). The TZ in the medial structure of carotid artery tripods is exclusively localized in the ICA/ECA but not in the CCA. The ICA/ECA presented a TZ with a length up to 0.5 cm (4 probes; 25%), up to 1.5 cm (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%).

CONCLUSIONS

In this study we confirmed that in the carotid artery tripod, a TZ--an arterial segment with transition from elastic to muscular type--does exist, involving a variable length. Furthermore studies on the impact of the biomechanical properties of the TZ as a potential factor in atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ should be considered prior to interventional procedures.

Fatal myocardial infarction in a young man caused by a right megadolicho-coronary artery with thrombosis: a case report

A case of fatal myocardial infarction in a young man, secondary to thrombosis of an isolated ectatic coronary artery, is reported. Histological study of this abnormal artery demonstrated that it was of elastic type in its proximal two centimeters. This abnormal arterial structure supports the hypothesis of a congenital defect.

Detection of red cell aggregation by low shear rate viscometry in whole blood with elevated plasma viscosity

The viscosity of whole blood measured at low shear rates is determined partly by shear resistance of the red cell aggregates present, stronger aggregation increasing the viscosity in the absence of other changes. Effects of cell deformability can confound interpretation and comparison in terms of aggregation, however, particularly when the plasma viscosity is high. We illustrate the problem with a comparison of hematocrit-adjusted blood from type 1 diabetes patients and controls in which it is found the apparent and relative viscosities at a true shear rate of 0.20 s-1 are lower in the patient samples than age matched controls, in spite of reports that aggregation is increased in such populations. Because the plasma viscosities of the patients were higher on average than controls, we performed a series of experiments to examine the effect of plasma protein concentration and viscosity on normal blood viscosity. Dilution or concentration by ultrafiltration of autologous plasma and viscosity measurements at low shear on constant hematocrit red cell suspensions showed (a) suspension viscosity at 0.25 and 3 s-1 increased monotonically with plasma protein concentration and viscosity but (b) the relative viscosity increased, in concert with the microscopic aggregation grade, up to a viscosity of approximately 1.25 mPa-s but above this the value the relative viscosity no longer increased as the degree of aggregation increased in concentrated plasmas. It is suggested that in order to reduce cell deformation effects in hyperviscous pathological plasmas, patient and control plasmas should be systematically diluted before hematocrit is adjusted and rheological measurements are made. True shear rates should be calculated. Comparison of relative viscosities at low true shear rates appears to allow the effects of red cell aggregation to be distinguished by variable shear rate viscometry in clinical blood samples.

Takayasu's arteritis and fibromuscular dysplasia as causes of acquired atypical coarctation of the aorta: retrospective analysis of seven cases

Coarctation of the aorta usually occurs in the aortic isthmus: however, 2% of all coarctation is localized at atypical sites such as the aortic arch and the thoracic and/or abdominal aorta. Causal therapy involves vascular surgery, and during the procedure, biopsies of the involved vessels should be taken to establish the etiology. This study involved the retrospective analysis of clinical and histopathological findings for seven patients who underwent vascular surgical procedures (age range, 10-37 years; male/female ratio 3:4). Histopathological analysis of specimens revealed two pathological processes taking place with different localization in the aortic wall as the cause of the atypical coarctation of the aorta: (1) fibrosis/scarification in the tunica media and adventitia compatible with chronic lesions of Takayasu's arteritis (four cases); (2) fibromuscular dysplasia in the tunica media (three cases).

The transitional zone in the tunica media of renal arteries has a maximal length of 10 millimetres

BACKGROUND

The goal of our study was to demonstrate and to determine the length of the transitional zone in the tunica media in renal arteries. The majority of renal artery atherosclerotic stenotic lesions occurs in this segment.

PATIENTS AND METHODS

Anatomical and histological studies were performed on 26 renal arteries from 13 adults at autopsy (mean age 61.6 years, range 33 to 87 years).

RESULTS

In the macroscopical examination the right renal arteries (RRA) were longer with a median 53.8 mm (range 38 to 65 mm) than the left renal arteries (LRA) with a median 47.6 mm (range 35 to 63 mm), the circumferences were nearly the same: RRA 10.9 mm (range 5 mm to 15 mm) and LRA 11 mm (range 5 mm to 15 mm). Probes for histological examinations were taken from three different regions of each renal artery (origin, 5 mm and 10 mm distal to the origin). We observed a typical elastic arterial structure at the origin and muscular types at the distal 10 mm region. At the distal 5 mm region variable ratios of elastic tissue (ET) and smooth muscle cells (SMC) were found as follows: 15 arteries presented an equal ratio of EM:SMC, 7 arteries presented ET > SMC and 4 arteries presented ET < SMC ratios.

CONCLUSIONS

In this study we confirmed that in renal arteries, a transitional zone (TZ) that is an arterial segment with transition from elastic to muscular type, does exist, involving the maximal length of 10 mm. Further studies on the impact of the biomechanical properties of the transitional zone as a potential localizing factor in renal atherosclerotic disease are justified. In addition, the complex biomechanical behavior of the TZ of the arterial wall should be taken into consideration when interventional procedures are planned.

Bladder tissue biopsies in spinal cord injured patients: histopathologic aspects of 61 cases

It was the aim of this histopathologic study to examine and compare results of bladder tissue biopsies in spinal cord injured (SCI) patients. The study group consisted of 61 SCI patients who received treatment at the Swiss Paraplegic Centre in Nottwil, near Lucerne, Switzerland. The mean age of the study group was 41 years (range, 17-73) and the mean duration of spinal cord lesion was 10 years and 4 months (range, 5 months to 44 years). The male:female ratio was 57:4. Bladder infections had occurred in each patient one to six times per year (median, 3.2). All samples were taken from the trigone of the bladder during endoscopic urologic procedures with a flexible cystoscope. Histopathologic analysis showed abnormal alterations of bladder tissue in 56 SCI patients (91.8%). Forty-six SCI patients (75.4%) had a chronic type and 10 SCI patients (16.4%) a subacute type of inflammation. Normal bladder tissue was found in five cases (8.2%). Further observation revealed the presence of fibrosis (34.4%), edema (9.8%), and lymphoid hyperplasia (6.6%). A t-test for independent samples showed a lack of significant correlation between the number of clinical bladder infections per year, the duration of injury, the neurologic level of the spinal cord lesion, and histopathologic types of infections.

Cholesterol depletion disrupts lipid rafts and modulates the activity of multiple signaling pathways in T lymphocytes

Lipid rafts are specialized plasma membrane microdomains, in which glycosphingolipids and cholesterol are major structural components. In T lymphocytes, several signaling proteins are associated with lipid rafts including the protein tyrosine kinase LCK and the adapter protein LAT. To investigate their importance in T cell signaling, lipid rafts were disrupted by depleting cholesterol with methyl-beta-cyclodextrin (MbetaCD). This transiently induced tyrosine phosphorylation of multiple proteins, including the ZAP-70 tyrosine kinase, its associated T cell antigen receptor zeta chain, LAT and phospholipase Cgamma1. Tyrosine phosphorylation was dependent on expression of LCK in lipid rafts. Depletion of cholesterol also resulted in activation of the Ras-ERK pathway. This was largely dependent on phorbol ester-sensitive protein kinase C (PKC) and the PKC-theta isoform translocated to the plasma membrane following MbetaCD treatment. MbetaCD did not stimulate intracellular Ca2+ fluxes; however, consistent with its ability to stimulate Ras, MbetaCD synergized with a Ca2+ ionophore to induce formation of the transcription factor NF-AT. These data indicate a crucial role for cholesterol in the regulation of signaling pathways in T cells, which is likely to reflect its importance in the formation of plasma membrane lipid rafts.

Inhibition of liposome-induced complement activation by incorporated poly(ethylene glycol)-lipids

Complement activation causes opsonization of foreign particles leading to particle elimination from the blood. Complement-mediated opsonization of charged and large liposomes presents a fundamental problem in their use to deliver therapeutic agents in vivo. To prolong the circulation half-lives of such liposomes, complement activation must be curtailed. The aim of this study was to assess the ability of poly(ethylene glycol)-lipids (PEG-lipids) to inhibit the in vitro activation of the classical pathway of complement in human serum by anionic liposomes. Incorporation of cholesterol-PEG600 (CH-PEG600), cholesterol-PEG1000 (CH-PEG1000), or phosphatidylethanolamine-PEG2000 (PE-PEG2000) resulted in dose-dependent inhibition of C1q binding and complement activation. The dose of PEG-lipid at which complement activation was blocked was inversely related to the PEG chain length. Complement activation was strongly inhibited when 15 mole% of CH-PEG600, 10 mole% CH-PEG1000, or 5 mole% PE-PEG2000 was incorporated into 100-nm anionic liposomes. PEG-lipid incorporation into larger liposomes (240 nm) was also successful in blocking C1q binding and complement activation. Radiolabeled cholesterol-PEG approximately 1400 was prepared and used to determine both the percentage of CH-PEG incorporated into the liposomes and the percentage maintained in the liposomes in the presence of 50% human serum at 37 degrees C for up to 24 h.

Toxin production by Burkholderia pseudomallei strains and correlation with severity of melioidosis

An exotoxin lethal to cells in culture (cytolethal toxin, CLT) was identified in culture filtrates of Burkholderia pseudomallei, the causative organism of melioidosis. CLT could pass through a 10-kDa cut-off ultrafilter and its properties suggest that it is a peptide. Isolates from soil, animals and man showed differential cytolethality in vitro. The isolates were divided into low, medium and high CLT producers with soil isolates being low producers and isolates from patients with melioidosis encephalitis being high producers. CLT levels are subject to regulation, as a strain isolated from an infected goat was one of the highest producers whereas the same strain isolated from soil was a low producer. In addition to CLT, all isolates produced a protein with cell-elongating activity which was also present in culture filtrates.

Glutamate transporter EAAC-1-deficient mice develop dicarboxylic aminoaciduria and behavioral abnormalities but no neurodegeneration

Four L-glutamate neurotransmitter transporters, the three Na(+)-dependent GLAST-1, GLT-1 and EAAC-1, and the Cl(-)-dependent EAAT-4, form a new family of structurally related integral plasma membrane proteins with different distribution in the central nervous system. They may have pivotal functions in the regulation of synaptic L-glutamate concentration during neurotransmission and are believed to prevent glutamate neurotoxicity. To investigate the specific physiological and pathophysiological role of the neuronal EAAC-1, which is also expressed in kidney and small intestine, we have generated two independent mouse lines lacking EAAC-1. eaac-1(-/-) mice develop dicarboxylic aminoaciduria. No neurodegeneration has been observed during a period of >12 months, but homozygous mutants display a significantly reduced spontaneous locomotor activity.