Effects of chronic hydrogen peroxide exposure on mitochondrial oxidative stress genes, ROS production and lipid peroxidation in HL60 cells

Hydrogen peroxide (H2O2) is a reactive species that is also involved in the redox regulation of cells because of it is relative stability. In numerous pathological situations, a chronic increase in the production of reactive species is observed, which is related to oxidative stress and cellular damage. This study aimed to evaluate the effects of long-term exposure to different H2O2 concentrations on oxidative stress biomarkers and mitochondrial dynamics in HL60 cells. HL60 cells were treated with a sustained production (0.1, 1.0 and 10.0 nM/s) of H2O2 for one hour. H2O2 production and malondialdehyde (MDA) levels, as a lipid peroxidation marker, increased progressively in HL60 cells in accordance with higher H2O2 exposure, with significant differences between the 10 nM/s H2O2 group and the control and 0.1 nM/s groups. Similarly, progressive increased expression in genes related to the mitochondrial antioxidant defences and mitochondrial dynamics were also observed. Significantly increased gene expression in the 10 nM/s H2O2 with respect to the control group was observed for manganese superoxide dismutase (MnSOD), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PCG1α), nuclear respiratory factor 2 (Nrf2), mitochondrial transcription factor A (Tfam), mitofusins 1 and 2 (Mfn1 and Mfn2) and uncoupling protein 3 (UCP3), whereas no significant changes were observed in the cytochrome c oxidase subunit IV (COXIV) gene expression. In conclusion, exposure to different sustained production of H2O2 is related to a progressive increase in the gene expression of mitochondrial dynamics and redox processes in HL60 cells, but also to oxidative damage at higher H2O2 production levels.

Oral antiseptics against coronavirus: in-vitro and clinical evidence

Angiotensin converting enzyme 2 (ACE2) is the cellular receptor for SARS-CoV-2, so ACE2-expressing cells can act as target cells and are susceptible to infection. ACE2 receptors are highly expressed in the oral cavity, so this may be a potential high-risk route for SARS-CoV-2 infection. Furthermore, the virus can be detected in saliva, even before COVID-19 symptoms appear, with the consequent high risk of virus transmission in asymptomatic/presymptomatic patients. Reducing oral viral load could lead to a lower risk of transmission via salivary droplets or aerosols and therefore contribute to the control of the pandemic. Our aim was to evaluate the available evidence testing the in-vitro and in-vivo effects of oral antiseptics to inactivate or eradicate coronaviruses. The criteria used were those described in the PRISMA declaration for performing systematic reviews. An electronic search was conducted in Medline (via PubMed) and in Web of Sciences, using the MeSH terms: ‘mouthwash’ OR ‘oral rinse’ OR ‘mouth rinse’ OR ‘povidone iodine’ OR ‘hydrogen peroxide’ OR ‘cetylpyridinium chloride’ AND ‘COVID-19’ OR ‘SARS-CoV-2’ OR ‘coronavirus’ OR ‘SARS’ OR ‘MERS’. The initial search strategy identified 619 articles on two electronic databases. Seventeen articles were included assessing the virucidal efficacy of oral antiseptics against coronaviruses. In conclusion, there is sufficient in-vitro evidence to support the use of antiseptics to potentially reduce the viral load of SARS-CoV-2 and other coronaviruses. However, in-vivo evidence for most oral antiseptics is limited. Randomized clinical trials with a control group are needed to demonstrate its clinical efficacy.

Simultaneous analysis of saturated and unsaturated oxylipins in 'ex vivo' cultured peripheral blood mononuclear cells and neutrophils

Oxylipins are a family of saturated and unsaturated fatty acids peroxidation products with bioactive properties. We have developed an improved method for the measurement of ex vivo oxylipin production by peripheral blood mononuclear cells (PBMCs) and neutrophils. We aimed to develop an analytical method to determine the production rates of polyunsaturated fatty acids (PUFAs), PUFA-oxylipin, and saturated-oxylipins by stimulated PBMCs and neutrophils based on solid phase extraction and HPLC-MS/MS technology. A UHPLC system coupled to a Q-Exactive Hybrid Quadrupole-Orbitrap mass spectrometer was used to identify and quantify oxylipin production. For each oxylipin and PUFA their differential response was calculated with respect to a deuterated internal standard factor (ISF). To calculate oxylipin and PUFAs in the culture samples, the individual ISF was used for each oxylipin and PUFA with respect to the deuterated internal standard. PBMCs and neutrophils showed a different pattern of oxylipin production and fatty acid secretion. Lipopolysaccharide (LPS) did not stimulate oxylipin production or fatty acids secretion in PBMCs, whereas phorbol myristate acetate (PMA) stimulation increased the production rate of 5-HETE, 15-HETE, 15-HEPE, 17-DoHE, PGE2, AA, and DHA. LPS stimulation decreased 16-hydroxyl-palmitatte (16-OHPAL) production and DHA secretion in neutrophils, while PMA stimulation increased the production rate of AA and its derivate oxylipins, 5-HETE, 15-HETE, and PGE2. In conclusion, we have developed a new method to determine oxylipins derived from both saturated and unsaturated fatty acids in culture cell media. This method has enough sensitivity, and accuracy, to determine oxylipin production and fatty acid secretion by PBMCs and neutrophils.

SNF472, a novel anti-crystallization agent, inhibits induced calcification in an in vitro model of human aortic valve calcification

The purpose of the present study was to investigate whether SNF472, the hexasodium salt of myo-inositol hexaphosphate (IP6 or phytate): 1. Inhibits induced calcification in cultured aortic valve interstitial cells (VIC) as an in vitro model of aortic valve stenosis and 2. Whether inhibition is different in VIC obtained from healthy and calcified aortic valves. VIC from healthy (n = 5) and calcified (n = 7) human aortic valves were seeded in basic growth medium, osteogenic differentiation medium alone, or in osteogenic medium with SNF472 (3, 10, and 30 μM) and cultivated for 3 weeks. Calcification was quantified spectrophotometrically after Alizarin Red staining. In VIC from calcified valves, a complete inhibition of calcification was observed with SNF472 concentrations of 10 and 30 μM (p < .01), significantly stronger than in VIC from healthy valves. When SNF472 was added to VIC after 1 week in osteogenic medium, 30 and 100 μM SNF472 inhibited the progression of ongoing calcification by 81 and 100% (p < .01), respectively. The same concentrations of SNF472 given after 2 weeks reduced calcification by 35 and 40% respectively (not significant). SNF472 inhibited both the formation and the progression of calcification with the strongest effect in VIC from calcified valves.

First-time-in-human randomized clinical trial in healthy volunteers and haemodialysis patients with SNF472, a novel inhibitor of vascular calcification

AIMS

SNF472 is a calcification inhibitor being developed for the treatment of cardiovascular calcification in haemodialysis (HD) and in calciphylaxis patients. This study investigated the safety, tolerability and pharmacokinetics (PK) of intravenous (IV) SNF472 in healthy volunteers (HV) and HD patients.

METHODS

This is a first-time-in-human, double-blind, randomized, placebo-controlled Phase I study to assess the safety, tolerability and PK of SNF472 after ascending single IV doses in HV and a single IV dose in HD patients. A pharmacodynamic analysis was performed to assess the capability of IV SNF472 to inhibit hydroxyapatite formation.

RESULTS

Twenty HV and eight HD patients were enrolled. The starting dose in HV was 0.5 mg kg^-1 and the dose ascended to 12.5 mg kg^-1 . The dose selected for HD patients was 9 mg kg^-1 . Safety analyses support the safety and tolerability of IV SNF472 in HD patients and HV. Most treatment-emergent adverse events were mild in intensity. No clinically significant effects were observed on vital signs or laboratory tests. PK results were similar in HD patients and HV and indicate a lack of significant dialysability. Pharmacodynamic analyses demonstrated that SNF472 administration reduced hydroxyapatite crystallization potential in HD patients who received IV SNF472 9 mg kg^-1 by 80.0 ± 2.4% (mean ± standard error of the mean, 95% CI, 75.3-84.8) compared to placebo (8.7 ± 21.0%, P < 0.001, 95% CI, -32.4 to 49.7).

CONCLUSION

The results from this study showed acceptable safety and tolerability, and lack of significant dialysability of IV SNF472. It is a potential novel treatment for cardiovascular calcification in end-stage renal disease and calciphylaxis warranting further human studies.

SNF472, a novel inhibitor of vascular calcification, could be administered during hemodialysis to attain potentially therapeutic phytate levels

BACKGROUND

Cardiovascular calcification (CVC) is a major concern in hemodialysis (HD) and the loss of endogenous modulators of calcification seems involved in the process. Phytate is an endogenous crystallization inhibitor and its low molecular mass and high water solubility make it potentially dialyzable. SNF472 (the hexasodium salt of phytate) is being developed for the treatment of calciphylaxis and CVC in HD patients. We aimed to verify if phytate is lost during dialysis, and evaluate SNF472's behaviour during dialysis.

METHODS

Dialyzability was assessed in vitro using online-hemodiafiltration and high-flux HD systems in blood and saline. SNF472 was infused for 20 min and quantified at different time points.

RESULTS

Phytate completely dialyzed in 1 h at low concentrations (10 mg/l) but not when added at 30 or 66.67 mg/l SNF472. In bypass conditions, calcium was slightly chelated during SNF472 infusion but when the system was switched to dialysis mode the calcium in the bath compensated this chelation.

CONCLUSION

Phytate dialyses with a low clearance. The administration of SNF472 as an exogenous source of phytate allows to attain supra-physiological levels required for its potential therapeutic properties. As SNF472 is infused during the whole dialysis session, the low clearance would not affect the drug's systemic exposure.

A novel pharmacodynamic assay to evaluate the effects of crystallization inhibitors on calcium phosphate crystallization in human plasma

Cardiovascular calcification (CVC) is a progressive complication of chronic kidney disease and a predictor of CV events and mortality. The use of biomarkers to predict CV risk and activities of potential or current treatment drugs in these patients could have a crucial impact on therapeutic approaches. Our aim was to develop a novel assay for measurement of the rate of calcium phosphate crystallization in human plasma and provide a tool to evaluate the effects of crystallization inhibitors. The efficacy of inhibitors was determined by adding inhibitory compounds (polyphosphates, fetuin-A, sodium thiosulfate or citrate) to control samples. The assay was additionally validated for SNF472, an experimental formulation of phytate being developed for the treatment of calciphylaxis and CVC in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). The method was repeatable and reproducible. The plasma crystallization rate was reduced up to 80% in a concentration-dependent manner following treatment with inhibitors in vitro, among which SNF472 was the most potent. This method appears beneficial in evaluating and discriminating between inhibitory activities of compounds such as polyphosphates on calcium phosphate crystallization, which present a novel therapeutic approach to treat CVC in ESRD patients.

Scuba diving enhances endogenous antioxidant defenses in lymphocytes and neutrophils

The aim was to study the effects of a scuba diving session on the lymphocyte antioxidant system, NO synthesis, the capability to produce reactive oxygen species and the antioxidant response in neutrophils. For that purpose seven male divers performed an immersion at a depth of 40 m for 25 min. The same parameters were measured after an hyperbaric oxygen (HBO) treatment at resting conditions in a hyperbaric chamber. Lymphocyte H2O2 production rose after diving and after HBO treatment. Glutathione peroxidase (GPx) and catalase activities increased after diving in lymphocytes, while after HBO exposure only increased GPx activity. Lymphocyte HO-1 mRNA expression increased after diving and after HBO exposure, while iNOS levels and nitrite levels significantly increased after diving. The hyperoxia associated to scuba diving leads to a condition of oxidative stress with increased lymphocyte H2O2 production, HO-1 expression, NO synthesis and antioxidant enzyme adaptations in order to avoid oxidative damage.

Evaluación de la arteriopatía de los miembros inferiores por tomografía computarizada multidetector comparada con la angiografía por sustracción digital

OBJECTIVE

To evaluate the diagnostic efficacy of multidetector computed tomography angiography (MDCTA) in lower limb arteriopathy (LLA) by comparing it with digital subtraction angiography (DSA).

MATERIAL AND METHODS

Twenty-four patients with LLA were studied. All patients underwent MDCTA (four detectors) and DSA, with double reading between the two techniques. Vascular territories were divided to facilitate analysis. Sensitivity (S), specificity (Sp), prevalence, positive and negative predictive values (PPV, PNV), and concordance (Kappa test) were evaluated. In third-portion arteries, the diagnostic performance of MDCTA was evaluated using an ROC curve.

RESULTS

MDCTA study to evaluate arterial pathology showed: Lower sensitivity in the study of the internal iliac artery (S: 0.65 and 0.71) with Sp 0.94 and 1. In the other vascular territories, S approached 1, with a slight decrease in Sp. Concordance with DSA was very high (kappa between 0.62 and 1) in all of the territories studied. MDCTA showed greater vessel longitude than DSA. In the third portion, the best diagnostic performance (ROC) was obtained in the reading of pathological vessels.

CONCLUSION

MDCTA was highly reliable in the study of LLA, with high concordance with DSA. In tortuous vessels, MDCTA depicted the lesions poorly; however, in straight vessels and third-portion vessels, MDCTA showed more vascular segments.

Vitamin C supplementation influences the antioxidant response and nitric oxide handling of erythrocytes and lymphocytes to diving apnea

OBJECTIVE

We have investigated the influence of vitamin C diet supplementation on the antioxidant response and nitrite levels in lymphocytes and erythrocytes during diving apnea.

SUBJECTS

Seven male professional apnea divers participated in a double blind crossover study. Divers were randomly assigned to either vitamin C supplemented or placebo groups. The subjects did not take any other supplements than the ones provided for this study.

INTERVENTION

One group was supplemented with vitamin C capsules (1 g per day) for 7 days while the other group took a placebo composed of lactose. The usual dietary habits of participants were assessed using a self-reported 7-days 24-h recall before the day of the study. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery.

RESULTS

Catalase activity increased in erythrocytes (23%) and superoxide dismutase increased in lymphocytes (35%) during the recovery only in the placebo group. Lymphocyte ascorbate levels increased in the supplemented group after diving (85%) and maintained high at recovery. Plasma nitrite levels increased about twofold in both groups during the recovery. Erythrocyte nitrite levels increased after diving (50%) and about twofold during the recovery in the supplemented group. Nitrite levels and iNOS levels in lymphocytes were higher in the placebo group than in the supplemented during the recovery. Erythrocyte carbonyl derivates were unchanged in all situations.

CONCLUSIONS

Vitamin C supplementation influenced the antioxidant response and NO handling in erythrocytes and lymphocytes to the oxidative stress induced by hypoxia-reoxygenation.

[Chronic mesenteric ischemia due to superior mesenteric artery stenosis. Percutaneous therapy as alternative treatment]

Chronic mesenteric arterial ischemia is an uncommon condition associated with a high morbidity and mortality. It is most commonly caused by atherosclerotic occlusive disease. Patients may suffer epigastric or periumbilical post-prandial pain ten to thirty minutes after eating. A case of chronic mesenteric ischemia is presented due to superior mesenteric artery stenosis. The diagnosis was performed with doppler sonography and angiography and was treated with percutaneous transluminal angioplasty. The patient became completely asymptomatic. The purpose of this report is to present the case, clinic and radiological features and to describe the percutaneous procedure. We believe that percutaneous treatment offers an improvement in this pathology with a low complication rate, decreasing the admission days and increasing patient comfort degree.

Intercellular junctions, apical differentiation, and infiltrative features in colon cancer: an ultrastructural study. The Colon Cancer Team at IMAS

Changes in the structure and number of cell junctions have been related to the infiltrative and metastatic potential of tumor cells. Apparently, the loss of cell adhesion should be coordinated with significant changes in the apical and basal cell domains. The authors have performed a sequential ultrastructural study of cells in the superficial, middle, and deep regions of well- and moderately differentiated colon adenocarcinomas. This was to investigate the differences in the organization of different membrane domains among tumor cells in the in situ areas, the advancing, infiltrative edge of the tumors, and the infiltrating zones between these two extreme zones. The results of the study suggest that the organization of these domains is not strictly coordinated, and that, for each infiltration level, both a settling and an infiltrating cell population can be found. These findings could explain the fact that apparently well-differentiated tumors are able to seed distant tissues with individual cells, rather than with well-differentiated glandular aggregates that would hardly be able to reach the vessel lumina without significantly modifying their organization.

In vitro activities of 22 antimicrobial agents against Listeria monocytogenes strains isolated in Barcelona, Spain. The Collaborative Study Group of Listeriosis of Barcelona

The in vitro activity of 22 antimicrobial agents against 82 human Listeria monocytogenes strains isolated in Barcelona from 1994 to 1998 was determined. Ampicillin and gentamicin showed good in vitro activity against all strains (MIC90: 1 and < or = 0.25 microg/ml, respectively). No resistance to rifampin or co-trimoxazole was detected and only one strain was resistant to tetracycline. Of the nine fluoroquinolones tested, clinafloxacin and gemifloxacin were the most active compounds (MIC90: 0.12 and 0.25 microg/ml, respectively). No increasing MICs values were observed during the five-year period.

Signet ring epithelioid stromal tumor of the small intestine

Cells having a signet ring appearance can occur in mesenchymal, lymphoid, and other nonepithelial neoplasms. We report the case of an intestinal stromal tumor with smooth muscle differentiation and a prominent signet ring cell component. The presence of signet ring forms of smooth muscle cells in sections of paraffin-embedded tissue often contrasts with a lack of cytoplasmic spaces by electron microscopy, and the ultrastructural finding of signet ring-like areas in the present case can be attributed to the fact that the tissue for electron microscopy was retrieved from paraffin blocks where this peculiar artifact already existed. Ultrastructural examination of the signet ring-like areas suggests that they originated as retraction spaces which may have resulted from variations in intracellular tension forces related to the distribution of actin filaments.

Clear cell meningioma of the lumbo-sacral spine with chordoid features

Clear cell meningioma (CCM) is a peculiar variant that differs from conventional meningioma in affecting younger patients, arising more often in spinal or cerebellopontine locations, and showing a higher recurrence rate. Classical meningothelial areas are scarce in these tumors and the differential diagnosis with other neoplasms, particularly metastatic carcinoma, is often difficult. We report a case of clear cell meningioma from the lumbosacral spine in which location, radiologic presentation, light microscopic appearance in initial sampling, and some of the ultrastructural findings were reminiscent of chordoma. The tumor cells were diffusely positive for vimentin and very focally positive for epithelial membrane antigen. Ultrastructural demonstration of interdigitating cell processes joined by numerous desmosomes confirmed the diagnosis of CCM.

Initial numbers, serovars and phagevars of Listeria monocytogenes isolated in prepared foods in the city of Barcelona (Spain)

A total of 1100 samples of prepared foods purchased in restaurants and delicatessen shops in the city of Barcelona was examined for the presence of Listerio. L. monocytogenes was more frequently isolated from foods intended to be consumed without further cooking (9.3%) than from foods intended to receive further cooking prior to consumption (2.9%). A quantitative study, carried out with 773 samples, yielded 1% of samples with numbers of L. monocytogenes higher than 100 CFU/g. Strains of L. monocytogenes belonged to serovar 4b (36.3%), 1/2a (29.5%), 1/2b (22.7%) and 1/2c (11.3%). L. monocytogenes serovar 4b phagevar 3274: 2671 (6 of 11) was prevalent among the strains studied.

[Psoas abscess secondary to lumbar spondylodiscitis caused by gram negative bacilli]

The association between psoas abscess and lumbar spondylodiscitis by Gram negative bacilli represents a rare clinical entity. Sometimes the absence of demonstrative symptoms complicates the diagnostic schema. We report about a 72 year-old woman, without previous known diabetes mellitus, who was admitted because of fever of one week duration and a non-ketotic hyperosmolar coma. A left psoas abscess was identified by abdominal computed tomography (CT). The abscess was in communication with the L1-L2 intervertebral space. Although Escherichia coli was identified as the causing agent and appropriate antibiotic therapy was administered, the resolution of the abscess occurred only after the implantation of a percutaneous catheter guided by CT without additional surgery. Percutaneous drainage as a diagnostic-therapeutic technique has rendered the surgery as the last resort in the treatment of psoas abscess.

Perinatal listeriosis: a population-based multicenter study in Barcelona, Spain (1990-1996)

The aim off this study was to describe the incidence, epidemiology, clinical presentation, and outcome of perinatal listeriosis for a 7-year period (1990-1996) based on data of an active population-based surveillance project implemented in the city of Barcelona, Spain. There were 30 cases (20.8%) associated with pregnancy (15 pregnant women, 13 neonates, and 2 fetal deaths). The incidence of perinatal listeriosis varied from 4.1 to 0 per 10,000 live births. The proportion of perinatal cases in relation to the total number of cases of listeriosis varied between 0 and 42%. Early-onset neonatal sepsis accounted for 12 of 13 live births. The mean age of infected pregnant women with listeriosis was 30.1+/-2.0 years. Chorioamnionitis was the predominant clinical form (86.7%). Only two mothers had primary bacteremia by L. monocytogenes in the second trimester of pregnancy. Both infants were born healthy, without signs of infection. One of these mothers was infected with the human immunodeficiency virus (HIV). Since January 1994, 12 strains were available for serotyping and phagotyping; 9 belonged to serovar 4b, 2 to serovar 1/2b, and 1 to serovar 1/2a. No outbreaks of L. monocytogenes infection occurred during the study period. The overall neonatal mortality rate was 7.7% among infected live births. All pregnant women were treated with ampicillin and none died. Early antenatal treatment with ampicillin improves neonatal outcome and can result in the birth of healthy babies.

[Transthoracic needle aspiration biopsy. The diagnostic accuracy of pulmonary lesions]

We performed 91 transthoracic functions, under fluoroscopy, sonographically or by computed tomography control, at Clinic Hospital in Valencia. The procedures was performed with Chiba needle 22 gauges while the cytopathologist was present. Maximum number of needle passes was four. Malignant diagnosis has been obtained in 64.8% of cases, in 12 patients a benign diagnosis was obtained and confirmed, 13 cases were false negative and the specimen was insufficient for diagnosis in 7 (5 of them lesions had a diameter less than 2 cm). The study showed 82% for sensitivity, 100% for specificity and 85% for accuracy. The punction was guided by fluoroscopy in 49 patients, by sonography in 6 and by computed tomography control in 36. The accuracy diagnosis for fluoroscopy guidance was 96%. The complications were 9 (9.9%): Two patients presented minor hemoptysis resolved spontaneously, 6 patients showed minor pneumothorax and one patient was treated a cause of a large pneumothorax. We concluded that transthoracic biopsy is a simple and save technique that can provide a high diagnosis accuracy in patients with pulmonary pathology.

[Percutaneous nephrostomy. Review of 92 cases]

Presentation of 92 nephrostomies percutaneous in 70 patients. Nephrostomy was bilateral in 5 cases. Three patients had collections of renal origin (2 urinomas and 1 abscess) which were treated percutaneously. The indication for nephrostomy was in all cases obstruction of the collector system, with one exception where the indication was ureteral fistula. Origin was lithiasis in 53 cases, 15 cases vesical carcinoma, 3 post-surgical iatrogenic stenosis, 1 fistula and formation of urinoma after lithotrity, 5 prostate carcinoma infiltration, 8 infectious origin, 4 congenital and 1 due to glandular cystitis. 9 patients were monorenal. In 6 patients leucocytosis was present, 4 has fever, and in 11 coexisted fever and leucocytosis. High creatinine and urea levels were present in 55.7% and 41% patients, respectively.. Renal puncture through lower calyceal group was the preferred option. Purulent urine was obtained in 17 cases. With regard to nephrostomy complications haematuria occurred in 30 cases (only in 9 it lasted more than 1 day); and there was 1 case of pararenal haematoma. Pain was significant in 12% procedures and contrast extravasation resulted in 14% cases (in all of them proper positioning of nephrostomy catheter was possible). Spontaneous expulsion and the subsequent replacement of the catheter occurred in 12 cases. On average, residence time of catheter was 44.8 days. In all cases both the patient's signs and symptoms, and the laboratory results were improved.

Intestinal carriage of campylobacters, salmonellas, yersinias and listerias in pigeons in the city of Barcelona

The faecal bacterial flora of pigeons, which may be the source of infectious diseases in man, was studied in the city of Barcelona. Four hundred cloacal specimens were examined for Campylobacter jejuni, Camp. coli, Salmonella spp., Yersinia spp. and Listeria spp., over a 12 month period. Campylobacter jejuni was the most frequently isolated micro-organism, found in 105 pigeons (26.2%), with a greater incidence in the districts of the city with a high density of pigeons and without seasonal variation. Salmonella spp. were isolated from six specimens (1.5%) and Yersinia intermedia was isolated from only one pigeon.

Dynamic MR imaging of liver tumors: analysis with temporal reconstruction images

PURPOSE

To graphically display the time dependency of contrast enhancement of liver tumors at examination with dynamic magnetic resonance (MR) imaging.

MATERIALS AND METHODS

A temporal reconstruction image was generated by obtaining a line of interest drawn on a single image through the liver and the tumor and reformatted over a sequence of temporal images. This calculated image expressed the temporal evolution of the line, including nontumoral liver and tumor, with regard to three variables: signal intensity, enhancement, and velocity. This allowed a visually integrated analysis of 95 hepatic lesions studied with dynamic single-section MR imaging after contrast material administration.

RESULTS

Temporal reconstruction images were obtained for all the dynamic studies. Five patterns of enhancement based on signal intensity and velocity variations coupled with morphologic information were found: wall, diffusion, moderate enhancement, marked progressive, and early intense patterns.

CONCLUSION

Temporal reconstruction of liver tumors after contrast material administration can be used to analyze, describe, and report the dynamics of lesion enhancement with morphologic and temporal resolution.

[Application of molecular epidemiology techniques in the study of food poisoning caused by Staphylococcus aureus]

BACKGROUND

The use of molecular epidemiology techniques has provided better knowledge as to the clonal organization of bacterian populations and thus allows better follow up of epidemics. An alimentary toxiinfection in a Barcelona school produced by Staphylococcus aureus was analyzed by the combination of epidemiologic, phenotype and genotype markers with the aim of determining the source of the alimentary contamination.

METHODS

Nine strains of Staphylococcus aureus isolated in 6 food manipulators and 3 patients were studied with the following markers: biotype, antibiotype, phagotype, plasmid profile, polymorphism of the size of the restriction fragments of total DNA and ribotype.

RESULTS

Epidemiologic study of the strains analyzed showed that both the phenotype markers and the plasmid profile are thecniques of little discriminatory value. The only clearly discriminatory technique used was ribotyping which defined 3 clones in the 9 strains of Staphylococcus aureus studied.

CONCLUSIONS

Molecular study of isolated strains of Staphylococcus aureus was able to identify the causal origin of the alimentary toxiinfection in one of the 6 food manipulators studied.

[Diagnostic effectiveness of CT and MR in local staging of renal tumors]

The aim of this paper is to study the pre-operative staging of renal tumours, comparing CT and MR, and the imaging criteria used, examining the diagnostic efficacy for each of them. Thirty-four tumours were obtained from 29 patients. All cases were studied with CT and MR. To measure diagnostic efficacy, both for each technique and the criteria used in 2 different readings, a diagnostic performance curve (DPC) is calculated. Neither CT nor MR show infiltration of renal capsule. With regard to perinephritic fat, fascia and adjacent organ invasion, both techniques lead to overstaging, mainly CT. When applying more conservative reading criteria, the results are much improved, specially in relation to CT, although results with MR continue to be more favourable. MR is better to study vascular invasion, providing no false results. Of 22 tumours undergoing surgery, first option was the correct staging in 14 tumour with CT and in 16 with MR. When selecting the best imaging technique to stage renal tumours, MR allows a better and simpler radiologic reading. Nevertheless, considering the high correlation between CT and MR, CT can be used more reliably in institutions where no easy access to a MR unit is available. Both CT and MR overstage renal tumours.

[Secondary arterial hypertension in type I neurofibromatosis (NF-1). Findings in 6 patients]

With the aim to analyze the association of Type I Neurofibromatosis with secondary arterial hypertension, a retrospective study has been performed on 36 patients, diagnosed of pheochromocytoma (n = 12) and/or renal artery stenosis (n = 25), finding in 6 of them diagnostic criteria of Type I neurofibromatosis, of these 4 showed pheochromocytoma, 1 renal artery stenosis and 1 pheochromocytoma plus renal artery stenosis. CAT and angiography were the best diagnostic imaging methods to confirm clinic and biological suspicion of adrenal tumor of renal artery stenosis. It is recommended the systematized study of patients with NF-1 together with their relatives who phenotypically show some illness stigma, or with arterial hypertension resistant to conventional treatment.

Incidence of Listeria monocytogenes in fresh foods in Barcelona (Spain)

From September 1989 to March 1990, a study of Listeria spp. was carried out on 311 samples of raw foodstuffs from markets and other establishments in the city of Barcelona. These foodstuffs included vegetables (103 samples), minced meats from pork, beef and poultry (168 samples) and bivalve molluscs (40 samples). L. monocytogenes was isolated in 7.8% of the vegetable samples, 17.3% of the minced meats and in 7.5% of bivalve molluscs. The most frequent serovars were 1/2 and 4. Other species isolated were L. innocua, L. welschimeri and L. seeligeri.

[Insulin and peptide C secretion after food ingestion and the interaction of insulin with its erythrocyte receptor in a family with MODY type diabetes mellitus]

In 12 members of a family with MODY, insulin and C-peptide release after intake of a test breakfast was measured as well as binding of insulin to its erythrocyte receptor. According to serum glucose concentrations, subjects were classified into: diabetic, carbohydrate intolerant, and normal subjects. The two diabetic patients had an insulin release pattern similar to that of non-insulin dependent diabetics. The two patients with carbohydrate intolerance presented hyperinsulinism either at base state and after stimulation. Of the eight normal subjects, three presented high concentrations of serum insulin either at base level and after stimulation; in the remaining five, base insulinemia was normal and the response after food intake was poor. Insulin binding to the receptor was decreased in diabetic patients and this anomaly was more evident in patients with carbohydrate intolerance. In the three patients with increased serum insulin concentration, no disturbances in insulin-receptor binding were detected; in the remaining five patients, insulin-receptor binding was significantly decreased. Our findings prove that these subjects present a disturbance of insulin release and an impairment of insulin-receptor binding with a predominance of one or the other alteration even before hyperglycemia is evident.