Comparison of homogenization with the GentleMacs Dissociator vs conventional methods for routine tissue processing.

Tissue specimens are valuable materials for microbiological diagnosis. The method of tissue processing can have a significant effect on sensitivity. This study aimed to compare different biopsy processing methods in terms of efficacy and standardization. Pork tissue artificially inoculated with Staphylococcus aureus and Escherichia coli, and samples of infected human tissue were processed by different methods before culture, and the results compared. Bacterial recovery from artificially inoculated pork tissue was significantly higher by homogenization with GentleMacs Dissociator than with sonication. No significant difference was observed between the GentleMacs Dissociator and manual treatment with a scalpel and vortexing. The microbial yield from homogenized human tissues was significantly higher after homogenization with GentleMacs Dissociator than with the conventional method. Homogenization with the GentleMacs Dissociator retrieves bacteria from tissue effectively. Tissue homogenization with the Dissociator is easy and fast to perform and allows for a high degree of standardization.

A 'fragile cell' sub-population revealed during cytometric assessment of Saccharomyces cerevisiae viability in lipid-limited alcoholic fermentation.

AIMS: To show that in anaerobic fermentation with limiting lipid nutrients, cell preparation impacts the viability assessment of yeast cells, and to identify the factors involved. METHODS AND RESULTS: Saccharomyces cerevisiae viability was determined using propidium iodide staining and the flow cytometry. Analyses identified intact cells, dead cells and, under certain conditions, the presence of a third subpopulation of apparently damaged cells. This intermediate population could account for up to 40% of the entire cell population. We describe, analyse and discuss the effects of different solutions for cell resuspension on the respective proportion of these three populations, in particular that of the intermediate population. We show that this intermediate cell population forms in the absence of Ca(2+)/Mg(2+). CONCLUSIONS: Cell preparation significantly impacts population viability assessment by FCM. The intermediate population, revealed under certain conditions, could be renamed as 'fragile cells'. For these cells, Ca(2+) and Mg(2+) reduce cell membrane permeability to PI. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that analyses and discusses the factors influencing the formation of an intermediate population when studying viability in yeast alcoholic fermentation. With a wider application in biological research, this study provides important support to the relatively new questioning of propidium iodide staining as a universal cell death indicator.

[Chronic cough in childhood]. / Toux chronique de l'enfant.

INTRODUCTION: Although less frequent than viral induced recurrent cough; chronic cough remains a sometimes difficult to resolve diagnostic tool. STATE OF THE ART: Most authors estimate that a cough can by considered as chronic after three weeks of duration. Few papers have been published concerning etiologic diagnosis of chronic cough in childhood but these indicate the same main causes as in adults: cough variant asthma, postnasal drip syndrome, gastro-esophageal reflux. Nevertheless, each age bracket presents specific diagnosis: malformations between zero and one year, psychogenic cough in adolescents. PERSPECTIVES: New techniques as induced sputum studies helps to refine chronic cough diagnosis in childhood (after 7 years). Eosinophilic bronchitis, associated or not to bronchial hyperresponsiveness has important therapeutic consequences because associated with a favourable response to corticosteroids. Other techniques will be developed in the future (exhaled NO for example). CONCLUSIONS: Chronic cough in childhood must be investigated from an anatomic point of view and on frequency arguments. Control and removal of the cough will only be obtained if a precise diagnosis and a suitable treatment are reached.

Resistance to vasopressin action on the kidney in patients with Cushing's disease.

OBJECTIVE: To assess the plasma levels and action of arginine vasopressin (AVP) in patients with Cushing's disease. There are many reports that patients with Addison's disease have increased AVP levels associated with hyponatraemia and hypoosmolality, but none on the dynamics of secretion of this neurohormone during osmolality-based stimulation in patients with chronic hypercortisolism. DESIGN AND SUBJECTS: The plasma AVP concentration and the urinary and plasma osmolality after a 7.5-h water deprivation test (WDT) were evaluated in 13 patients with Cushing's disease and 15 normal (control) individuals. In patients with Cushing's disease we also assessed the urinary osmolality in response to 10 micrograms i.v. desmopressin (DDAVP) administered at the end of the WDT. RESULTS: At the end of the WDT, urinary osmolality was significantly lower in patients with Cushing's disease (511.5 +/- 148.5 mOsm/l) than in the normal subjects (981.1 +/- 107.1 mOsm/l, P < 0.001), whereas plasma osmolality did not differ between the two groups. Consequently, the urine/plasma osmolality ratio (Uosm/Posm) was lower in patients with Cushing's disease than in normal individuals (1.8 +/- 0.5 compared with 3.4 +/- 0.4, P < 0.001). The AVP concentration also was greater (7.3 +/- 3.1 pmol/l) in those with Cushing's disease than in the controls (3.9 +/- 2.3 pmol/l, P < 0.005). After administration of DDAVP to the hypercortisolaemic patients, the urinary osmolality attained (718.0 +/- 200.0 mOsm/l) was still lower than that in the normal group at the end of WDT (P < 0.005). CONCLUSIONS: Patients with Cushing's disease presented higher AVP levels and smaller Uosm/Posm ratios than normal subjects. After DDAVP, the patients with Cushing's disease were unable to concentrate the urine adequately. These data suggest that the kidney shows resistance to the action of both endogenous and exogenous AVP in patients with Cushing's disease.

Association between latex sensitization and repeated latex exposure in children.

BACKGROUND: Children with spina bifida are at greater risk for latex and ethylene oxide sensitization. The authors' aim in this study was to evaluate the role of previous surgical procedures in the development of sensitization to latex and ethylene oxide. METHODS: The authors investigated 80 children 1-16 yr old, separated into 3 groups. Two groups had a history of 3 or more general anesthetics: 29 children had spina bifida (spina bifida group) and 31 had undergone multiple surgeries for another disease (multiple surgeries group). A control group of 20 children had undergone less than 1 anesthetic. Clinical manifestations with latex, perioperative anaphylactic reactions, and number of previous anesthetics were recorded. Skin prick tests with a commercial extract of latex, four common inhalant allergens, and radioallergosorbent test to latex and ethylene oxide were performed. RESULTS: The three groups did not differ significantly with respect to age, sex, and atopic status. Mean number of anesthetics was comparable in the spina bifida and the multiple surgeries group. Latex sensitization was common in the spina bifida group (59%) and in the multiple surgeries group (55%) but not in the control group (0%, P < 0.05). Ethylene oxide sensitization was significantly more frequent in the spina bifida group than in the multiple surgeries group (44% vs. 19%; P = 0.052) and strongly associated with latex sensitization. Mean number of previous anesthetics was greater in children sensitized to latex (8.4 vs. 3.9; P < 0.05). CONCLUSION: Results suggest that it is the number of surgical procedures rather than spina bifida per se that is related to sensitization to latex.

Is systematic preoperative screening for muscle relaxant and latex allergy advisable?

We investigated a female population prior to general anaesthesia, using skin prick tests with latex and muscle relaxants to appraise the validity and feasibility of a systematic preoperative screening for these substances. Anaesthetists performed skin tests, and positive and doubtful tests were checked in our allergy department. Of 114 patients, 42 had uninterpretable tests because of dermographism (28 patients) or suppression of skin reactivity (14 patients). Among the other 72, nine had a positive or doubtful test to latex, and seven a positive or doubtful test to one or more muscle relaxants. After checking, only four sensitizations to latex and one to muscle relaxant were confirmed. In conclusion, a systematic screening for latex and muscle relaxant allergy is not advisable. In contrast, screening for latex allergy in selected high-risk groups (spina bifida, health-care workers) is necessary.

[Reactions to iodine contrast media]. / Réactions aux produits de contraste iodés.

Contrast media are used in many radiological examinations, but they are responsible for 4.6 to 8.5 percent of the toxic or anaphylactoid adverse reactions observed. The early contrast media were hyperosmolar, whereas those in current use are isosmolar and either ionic or non-ionic. The patient's age, the presence of a pre-existing disease and a history of adverse reactions to contrast media are the most important risk factors. Seventeen to 35 percent of these reactions recur. Several physiopathological mechanisms have been blamed for adverse reactions to contrast media, including complement activation, histamine release, recruitment of inflammation mediators, and antigen-antibody reaction. There is no paraclinical examination that can diagnose or predict such reactions. Various preventive tests have been studied and applied to individuals with or without history of reaction. In a population of patients with previous reaction, the administration of corticosteroids 12 h and 2 h before the radiological examination resulted in a significant reduction of the number of reactions. In patients at risk (i.e. those with previous reactions of this kind) the results varied, but in these 2 groups of subjects non-ionic products given either alone or with corticosteroids or H1-antihistaminics reduced to 1 percent the incidence of reactions. So far, tachyphylaxis has virtually played no role compared with these preventive treatments. It is concluded that patients with a history of anaphylactoid reactions who must receive another injection of contrast medium, a non-ionic product and/or the H1-antihistaminic-corticosteroid combination should be used.

[Acute bronchospasm due to periwinkle alkaloid and mitomycin association]. / Bronchospasme aigu d à l'association alcaloïde de la pervenche-mitomycine.

We report six cases in which patients presented with acute dyspnoea following injections of either vindesine or vinorelbin. These patients were receiving chemotherapy in association with cisplatin, mitomycin, and vindesine or vinorelbin, for inoperable bronchial cancer. Three of the patients had evidence of airflow obstruction before these incidents. The clinical picture suggested bronchospasm and appeared in the two hours following an injection of the vinca alkaloid and a significant time away from the administration of the mitomycin. Additional respiratory support was necessary in one patient, the bronchial spasm stopped spontaneously in three cases, and following bronchodilator in two. The respiratory toxicity of vinca alkaloids (vindesine, vinblastin) was observed in 4% of the cases, uniquely when they were associated with mitomycin. Vinorelbin seems to possess the same respiratory toxicity. The bronchospasm, sometimes very severe, seems to occur in the two hours following the injection in the case of the cytotoxics and some time after the administration of mitomycin. The recurrence of the bronchospasm is a constant feature when the vinca alkaloid is readministered. This side effect is different to the pulmonary fibrosis due to mitomycin. Clinical follow up and spirometry is thus necessary in those patients receiving chemotherapy in which vinca alkaloids and mitomycin are associated and the regime should be followed after each administration of a vinca derivative. After the first episode of dyspnoea, it is probably wise to stop the administration of these anti-mitotics to prevent any further respiratory side-effects which could be more severe.

[Characteristics of allergic asthma]. / Caractéristiques de l'asthme allergique.

The frequency of extrinsic (or allergic) asthma varies with age and sex. An inborn tendency to atopy, shown by a positive Phadiatop test or by skin tests positive to air-borne allergens, is found in 50% of asthmatic patients. The arguments in favour of the allergic origin of asthma are primarily clinical: same time and place of symptoms in the typical form, frequent bouts of acute rhinitis, history of familial or personal atopy. The responsible allergen is often easily identified by questioning, and its nature can be confirmed by positive skin tests. The allergens most frequently involved are air-borne allergens, notably house dust mites furs or feathers of domesticated animals, and pollens. Compared with intrinsic asthma, extrinsic asthma has the following features: it begins at an earlier age, it is less severe, it seldom evolves towards chronic ventilatory impairment and, by definition, it implies that an allergen is responsible for the onset or worsening of the symptoms.

Abnormally increased iron concentration in basal ganglia in Shy-Drager syndrome. MR imaging and autonomic study.

Report of an early case of Shy-Drager syndrome in a 67 year-old woman patient. Autonomic failure was diagnosed by functional evaluation as well as laboratory tests. MR imaging disclosed a prominent putamina hypodensity in T2-weighted images at high field strength due to iron increased depositing in this basal ganglia. MR imaging evidences confirm Shy-Drager syndrome diagnosis, and contributes for differential diagnosis of idiopathic hypotension (pure autonomic failure) in special in SDS early cases.