A re-innervated in vitro skin model of non-histaminergic itch and skin neurogenic inflammation: PAR2-, TRPV1- and TRPA1-agonist induced functionality

Background

Skin, and epidermis, is innervated by sensory nerve fibres. Interactions between them and signal transduction are only partially elucidated in physiological/pathological conditions, especially in pruritus.

Objectives

To study the mechanisms involved in pruritus in vitro, we developed a skin explant model re‐innervated by sensory neurons.

Methods

This model is based on the co‐culture of human skin explants and sensory neurons from dorsal root ganglia of rats. Innervation and the expression of protease activated receptor 2 (PAR2), transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin one (TRPA1) was analysed by immunostaining. The response of the model to TRPV1, PAR2 and TRPA1 agonists was analysed by patch‐clamp, qPCR and enzyme‐linked immunosorbent assay.

Results

After 5 days of re‐innervating nerve fibres was evidenced in the epidermis. Re‐innervation was correlated with decrease of epidermal thickness and the number of apoptotic cells in the tissue. The major actors of non‐histaminergic itch (PAR‐2, thymic stromal lymphopoietin [TSLP], TSLP‐R, TRPA1 and TRPV1) were expressed in neurons and/or epidermal cells of skin explants. After topical exposure of TRPV1‐(Capsaicin), TRPA1‐(Polygodial) and PAR2‐agonist (SLIGKV‐NH₂) activation of reinnervating neurons could be shown in patch‐clamp analysis. The release of TSLP was increased with capsaicin or SLIGKV but decreased with polygodial. Release of CGRP was increased by capsaicin and polygodial but decreased with SLIGKV. Activation by SLIGKV showed a decrease of VEGF; polygodial induced an increase of TSLP, Tumour necrosis factor (TNF) and nerve growth factor and capsaicin lead to a decrease of sema3 and TNF expression.

Conclusion

The present model is suitable for studying itch and neurogenic inflammation pathways in vitro. We observed that activation of TRPV1, TRPA1 and PAR‐2 leads to different response profiles in re‐innervated skin explants.

Prediction of major adverse kidney events in critically ill burn patients

OBJECTIVE

We aimed at assessing the predictive value of plasmatic Neutrophil Gelatinase Associated Lipocalin (pNGAL) at admission and severity scores to predict major adverse kidney events (MAKE, defined as death and/or need for renal replacement therapy (RRT) and/or non-renal recovery at day 90) in critically ill burn patients.

MATERIAL AND METHODS

Single-center cohort study in a burn critical care unit in a tertiary center, including all consecutive severely burn patients (total burned body surface >20%) from January 2012 until January 2015 with a pNGAL dosage at admission. Reclassification of patients was assessed by Integrated Discrimination Improvement (IDI).

MEASUREMENTS AND RESULTS

87 patients were included. Mean age was 47.7 (IQ 25-75: 33.4-65.2) years; total burn body surface area was 40 (IQ 25-75: 30-55) % and ICU mortality 36%. 39 (44.8%) patients presented a MAKE, 32 (88.9%) patients died at day 90. pNGAL was higher in the MAKE group (423 [IQ 25-75: 327-518]pg/mL vs 184 [IQ 25-75: 147-220]pg/mL, p<0.001). In multivariate analysis, pNGAL and abbreviated burn severity index (ABSI) remained associated with MAKE (OR 1.005 [CI 95% 1.0005-1.009], p=0.03 and OR 1.682 [CI95%1.038-2.726], p=0.035 respectively). Adding pNGAL to abbreviated burn severity index, simplified organ failure assessment and the simplified acute physiology score 2 did outperform clinical scores for the prediction of MAKE and AKI and for most severe forms of AKI and allowed a statistically significant reclassification of patients compared to ABSI for MAKE, RRT, AKI at Day 7 and AKI during hospitalization with a number of patients needed to screen to detect one extra episode of MAKE was 44, 13 for severe AKI and 15 for AKI.

CONCLUSIONS

pNGAL at admission is associated with the risk of MAKE in this population, and outperform severity scores when associated. Interventional studies are now needed to assess if impact of biomarkers-guided strategies would improve outcome.

Increased Fatty Acid Oxidation in Differentiated Proximal Tubular Cells Surviving a Reversible Episode of Acute Kidney Injury

BACKGROUND/AIMS

Fatty acid oxidation (FAO), the main source of energy produced by tubular epithelial cells in the kidney, was found to be defective in tubulo-interstitial samples dissected out in kidney biopsies from patients with chronic kidney disease (CKD). Experimental data indicated that this decrease was a strong determinant of renal fibrogenesis, hence a focus for therapeutic interventions. Nevertheless, whether persistently differentiated renal tubules, surviving in a pro-fibrotic environment, also suffer from a decrease in FAO, is currently unknown.

METHODS

To address this question, we isolated proximal tubules captured ex vivo on the basis of the expression of an intact brush border antigen (Prominin-1) in C57BL6/J mice subjected to a controlled, two-hit model of renal fibrosis (reversible ischemic acute kidney injury (AKI) or sham surgery, followed by angiotensin 2 administration). A transcriptomic high throughput sequencing was performed on total mRNA from these cells, and on whole kidneys.

RESULTS

In contrast to mice subjected to sham surgery, mice with a history of AKI displayed histologically more renal fibrosis when exposed to angiotensin 2. High throughput RNA sequencing, principal component analysis and clustering showed marked consistency within experimental groups. As expected, FAO transcripts were decreased in whole fibrotic kidneys. Surprisingly, however, up- rather than down-regulation of metabolic pathways (oxidative phosphorylation, fatty acid metabolism, glycolysis, and PPAR signalling pathway) was a hallmark of the differentiated tubules captured from fibrotic kidneys. Immunofluorescence co-staining analysis confirmed that the expression of FAO enzymes was dependent of tubular trophicity.

CONCLUSIONS

These data suggest that in differentiated proximal tubules energetic hyperactivity is promoted concurrently with organ fibrogenesis.

Undetectable haptoglobin is associated with major adverse kidney events in critically ill burn patients

BACKGROUND

Intravascular haemolysis has been associated with acute kidney injury (AKI) in different clinical settings (cardiac surgery, sickle cell disease). Haemolysis occurs frequently in critically ill burn patients. The aim of this study was to assess the predictive value of haptoglobin at admission to predict major adverse kidney events (MAKE) and AKI in critically ill burn patients.

METHODS

We conducted a retrospective, single-centre cohort study in a burn critical care unit in a tertiary centre, including all consecutive severely burned patients (total burned body surface > 20% and/or shock and/or mechanical ventilation at admission) from January 2012 to April 2017 with a plasmatic haptoglobin dosage at admission.

RESULTS

A total of 130 patients were included in the analysis. Their mean age was 49 (34-62) years, their median total body surface area burned was 29% (15-51%) and the intensive care unit (ICU) mortality was 25%. Early haemolysis was defined as an undetectable plasmatic haptoglobin at admission. We used logistic regression to identify MAKE and AKI risk factors. In multivariate analysis, undetectable haptoglobin was associated with MAKE and AKI (respectively, OR 6.33, 95% CI 2.34-16.45, p < 0.001; OR 8.32, 95% CI 2.86-26.40, p < 0.001).

CONCLUSIONS

Undetectable plasmatic haptoglobin at ICU admission is an independent risk factor for MAKE and AKI in critically ill burn patients. This study provides a rationale for biomarker-guided therapy using haptoglobin in critically ill burn patients.

Rapid Occurrence of Chronic Kidney Disease in Patients Experiencing Reversible Acute Kidney Injury after Cardiac Surgery

BACKGROUND

There is recent evidence to show that patients suffering from acute kidney injury are at increased risk of developing chronic kidney disease despite the fact that surviving tubular epithelial cells have the capacity to fully regenerate renal tubules and restore renal function within days or weeks. The aim of the study was to investigate the impact of acute kidney injury on de novo chronic kidney disease.

METHODS

The authors conducted a retrospective population-based cohort study of patients initially free from chronic kidney disease who were scheduled for elective cardiac surgery with cardiopulmonary bypass and who developed an episode of acute kidney injury from which they recovered. The study was conducted at two French university hospitals between 2005 and 2015. These individuals were matched with patients without acute kidney injury according to a propensity score for developing acute kidney injury.

RESULTS

Among the 4,791 patients meeting the authors' inclusion criteria, 1,375 (29%) developed acute kidney injury and 685 fully recovered. Propensity score matching was used to balance the distribution of covariates between acute kidney injury and non- acute kidney injury control patients. Matching was possible for 597 cases. During follow-up, 34 (5.7%) had reached a diagnosis of chronic kidney disease as opposed to 17 (2.8%) in the control population (hazard ratio, 2.3; bootstrapping 95% CI, 1.9 to 2.6).

CONCLUSIONS

The authors' data consolidate the recent paradigm shift, reporting acute kidney injury as a strong risk factor for the rapid development of chronic kidney disease.

Impact of a preoperative conversational hypnotic session on propofol consumption using closed-loop anesthetic induction guided by the bispectral index: A randomized controlled trial

OBJECTIVE

The automated administration of propofol in a closed loop could be used to objectively evaluate the nonpharmacological anesthetic action of hypnotherapy. The objective of this study was to evaluate the impact of a conversational hypnosis session on the consumption of propofol for anesthetic induction.

DESIGN

A randomized, usual care-controlled, single-center, patient-blind trial.

SETTING

Tertiary care center in France from November 2012 to December 2013.

PARTICIPANTS

Adult patients scheduled for a surgical procedure under general anesthesia.

INTERVENTIONS

Before surgery, patients were randomized with a computer-generated random list for a preoperative conversational hypnosis session or for usual care. The conversational hypnosis session was conducted and individualized by the therapist with an academic degree in hypnosis in a quiet environment. Anesthetic induction was automatically performed by propofol without opioids and was assisted by the bispectral index in a closed loop.

OUTCOME

Primary endpoint was the propofol dose required for anesthesia induction, defined as a Bispectral index less than 60 for at least 30 seconds.

RESULTS

The study included 48 patients in the hypnosis group and 49 patients in the control group. No difference in propofol consumption to obtain anesthesia induction was observed between the groups (total dose: 138.6 [67.5] and 130 [47.9] mg, P = .47; adjusted dose: 2.15 [1.09] and 1.95 [0.66] mg/kg, P = .28, for the hypnosis and control groups, respectively). Hetero-evaluation of arm movement during propofol injection (no reaction: 98% and 74%; P = .004, in the hypnosis and control groups, respectively) and face reaction at venous access placement (no reaction 59% and 30%; P = .017, in the hypnosis and control groups, respectively) were lower in the hypnosis group. No adverse event was reported.

CONCLUSIONS

No difference in propofol consumption was observed in this study designed to evaluate the effect of a hypnotic conversational session on anesthesia induction using an automated tool for propofol administration.

Evidence of dipstick superiority over urine microscopy analysis for detection of hematuria

BACKGROUND

There is an unresolved debate on the best screening method for hematuria as a symptom of glomerulonephritis or urological malignancies. The urinary dipstick is generally considered as an imperfect surrogate for urine microscopy analysis.

RESULTS

We designed a study to compare urine microscopy analysis, urinary dipstick and flow cytometry, using controlled dilutions of blood in urine samples from volunteers collected in two different physiologically-relevant conditions (basal state and hyperhydration). We found that although all techniques were 100 % effective in detecting hematuria at basal state, these results were variably reproduced when testing the same final amount of hematuria in urine collected after hyperhydration. Our data shows a variable sensitivity for the detection of hematuria by urine microscopy analysis or flow cytometry, but not by urinary dipstick.

CONCLUSIONS

Urinary dipstick qualifies as a better screening test for hematuria than urine microscopy analysis or flow cytometry, as it is sensitive and performs better in unstandardized conditions. It is universally available and also faster and cheaper than cytometric techniques.

Stress Response Gene Nupr1 Alleviates Cyclosporin A Nephrotoxicity In Vivo

Acute tubular damage is a major cause of renal failure, especially at the early phase of kidney transplant when ischemia-reperfusion injury and cyclosporin A toxicity may coexist. The mechanisms of the latter are largely unknown. Using an mRNA microarray on microdissected tubules from a rat model of cyclosporin A toxicity to describe the related epithelial-specific transcriptional signature in vivo, we found that cyclosporin A induces pathways dependent on the transcription factor ATF4 and identified nuclear protein transcriptional regulator 1 (Nupr1), a stress response gene induced by ATF4, as the gene most strongly upregulated. Upon cyclosporin A treatment, Nupr1-deficient mice exhibited worse renal tubular lesions than wild-type mice. In primary cultures treated with cyclosporin A, renal tubular cells isolated from Nupr1-deficient mice exhibited more apoptosis and ATP depletion than cells from wild-type mice. Furthermore, cyclosporin A decreased protein synthesis and abolished proliferation in wild-type tubular cells, but only reduced proliferation in Nupr1-deficient cells. Compared with controls, mouse models of ischemia-reperfusion injury, urinary obstruction, and hypertension exhibited upregulated expression of renal NUPR1, and cyclosporin A induced Nupr1 expression in cultured human tubular epithelial cells. Finally, immunohistochemical analysis revealed strong expression of NUPR1 in the nuclei of renal proximal tubules of injured human kidney allografts, but not in those of stable allografts. Taken together, these results suggest that epithelial expression of NUPR1 has a protective role in response to injury after renal transplant and, presumably, in other forms of acute tubular damage.

Evaluation of the ability of bone marrow derived cells to engraft the kidney and promote renal tubular regeneration in mice following exposure to cisplatin

It has been suggested that bone marrow derived stem cells have the ability to engraft the kidney and improve the outcome of severe acute kidney injury (AKI) in mice exposed to high doses of cisplatin, providing hope for cancer patients in whom irreversible renal damage occasionally occurs following the use of this highly effective anti-tumor drug. We tested the therapeutic potential of bone marrow derived cells injected during the acute phase (day 3 after cisplatin administration) of experimentally-induced AKI in C57Bl6/J mice, characterized by massive tubular necrosis, apoptosis, and a low proliferation capacity. We failed to show any benefit of bone marrow derived cells versus a regular homogenate of intact renal cells, or normal saline. Using cell tracers and flow cytometry, we demonstrated that bone marrow derived cells did indeed home to the bone marrow of the recipients but failed to settle in the kidney. Conversely, renal cells homed to injured kidneys. However, neither cell therapy protected the animals against cisplatin-induced death. We therefore question the short-term efficacy of bone marrow derived cells used to repair established injuries of the tubular epithelium.

Evolution of Hemodynamic and Functional Human Kidney Graft Dose Response to Dopamine Using an Implantable Doppler Device

OBJECTIVES

The relation between dopamine infusion and renal hemodynamics and function has not been studied in renal allografts during early recovery. We analyzed the dose response of dopamine infusion on renal blood flow and function in human kidney transplant recipients at reperfusion and during early graft recovery.

MATERIALS AND METHODS

Phasic and mean renal blood flow was measured by the pulsed Doppler technique using implantable Doppler microprobes in contact with the graft artery. Systemic and renal parameters were recorded on dopamine infusion (0, 3, 5, and 10 μg·kg⁻¹·min⁻¹) immediately after transplant (day 0) in 13 patients and at day 6 in 7/13 patients with early graft recovery. Results are expressed as median and interquartile range between the 25th and 75th percentiles.

RESULTS

RESULTS

At day 0, 3 μg·kg⁻¹·min⁻¹) dopamine did not increase mean renal blood flow over baseline (580 mL/min [219-663 mL/min] vs 542 mL/min [207-686 mL/min]; P = .84). There was an absence of effect with higher dopamine doses, whereas cardiac output, heart rate, and systolic and mean arterial pressure were significantly increased. Urinary sodium excretion, creatinine clearance, and urine output increased dose dependently, with a positive correlation between the increase in urine output and mean arterial pressure (r = 0.48, P < .001). At day 6, 3 μg·kg⁻¹·min⁻¹ dopamine increased mean renal blood flow over baseline (318 mL/min [234-897 mL/min] vs 191 mL/min [173-706 mL/min]; P = .016), with no further increase at higher doses.

CONCLUSIONS

Immediately after transplant, kidney grafts with ischemic-reperfusion injury are fully dilated and do not respond to dopamine. The specific renal effects observed are due to systemic hemodynamic status. Vascular responsiveness to a "renal dopamine dose" returns on graft recovery.

[Cardiac arrest in dialysis patients: Risk factors, preventive measures and management in 2015]

Patients undergoing hemodialysis have a 10 to 20 times higher risk of sudden cardiac arrest (SCA) than the general population. Sudden cardiac death is a rare event (approximately 1 event per 10,000 sessions) but has a very high mortality rate. Epidemiological data comes almost exclusively from North American studies; there is a great lack of European data on the subject. Ventricular arrhythmia is the main mechanism of sudden cardiac deaths in dialysis patients. These patients develop increased sensitivity mainly due to a high prevalence of severe ischemic heart disease and left ventricular hypertrophy and to a frequent trigger event: electrolytic and plasma volume shifts during dialysis sessions. Unfortunately, accurate predictive markers of SCA do not exist, however some primary prevention trials using beta-blockers or angiotensin II receptor blockers are encouraging, while the use of implantable cardioverter defibrillators in the population of chronic dialysis patients remains controversial. Identification of patients at risk, minimizing trigger events such as electrolytic shifts and improving team skills in the diagnosis and initial resuscitation with the latest recommendations from 2010 seem necessary to reduce incidence and improve survival in this high risk population. Organization of European studies would also allow a more accurate view of this reality in our dialysis units.

Epigenetic changes during sepsis: on your marks!

Epigenetics is the study of how cells, organs, and even individuals utilize their genes over specific periods of time, and under specific environmental constraints. Very importantly, epigenetics is now expanding into the field of medicine and hence should provide new information for the development of drugs. Bomsztyk and colleagues have detected major epigenetic changes occurring in several organs as early as 6 h after the onset of a mouse model of multiple organ dysfunction syndrome induced by Staphylococcus aureus lung injury. Decrease in mRNA of key genes involved in endothelial function was found to be associated with (and potentially explained by) a decrease in permissive histone marks, while repressive marks were unchanged. We discuss here the limitations of a whole-organ as opposed to a cell-specific approach, the nature of the controls that were chosen, and the pitfalls of histone modifications as a cause of the eventual phenotype. While the use of ‘epidrugs’ is definitely welcome in the clinic, how and when they will be used in sepsis-related multiple organ dysfunction will require further experimental studies.

Ex vivo analysis of renal proximal tubular cells

Background

Experimental models are inevitably a compromise between accurately reproducing a pathological situation and schematically simplifying it, which is intended to provide both relevance and conclusiveness. In-vivo models are very relevant, but multiple cell-types undergoing various changes may hinder the observation of individual molecular events.

Results

Here, we describe a method for analyzing and isolating specific cell types from the kidney and studying the phenotype they have acquired in vivo. Using flow cytometry, immunofluorescence, and RT-PCR, we show that our method is suitable for studying and isolating proximal tubular cells with an anti Prominin-1 antibody. Kidneys are subjected to mechanical dissociation followed by flow-cytometry analysis. Hundreds of thousands of proximal tubular cells are then isolated by magnetic separation followed by direct analysis or primary cell culture. Using our method, we detect phenotypic changes in the proximal tubular cells after renal ischemia reperfusion, and we isolate the proximal tubular cells, with a purity over 80%.

Conclusions

This method is efficient, quick, simple, and cheap, and should be useful for studying cell-type specific parameters after in vivo experimental studies. It is also a simple method to obtain a specific primary cell culture from any animal strain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-015-0058-4) contains supplementary material, which is available to authorized users.

Ultrasonographic evaluation of gastric content during labour under epidural analgesia: a prospective cohort study

BACKGROUND

Women in labour are considered at risk of gastric content aspiration partly because the stomach remains full before delivery. Ultrasonographic measurement of antral cross-sectional area (CSA) is a validated method of gastric content assessment. Our aim was to determine gastric content volume and its changes in parturients during labour under epidural analgesia using bedside ultrasonography.

METHODS

The cut-off value corresponding to an increased gastric content was determined by ultrasound measurement of antral CSA in six pregnant women in late pregnancy before and after ingestion of 250 ml of non-clear liquid. Antral CSA was then measured twice in 60 parturients who presented in spontaneous labour: when the anaesthesiologist was called for epidural analgesia catheter placement, and at full cervical dilatation. Patient-controlled epidural analgesia was performed with a solution of ropivacaine and sufentanil.

RESULTS

After liquid ingestion, antral CSA (mm(2)) increased from 90 (range, 80-151) to 409 (range, 317-463). A CSA of 320 was taken as cut-off value. The feasibility rate of antral CSA determination was 96%. CSA decreased from 319 [Q1 158-Q3 469] to 203 [Q1 123-Q3 261] during labour (P=2×10(-7)). CSA was >320 in 50% of parturients at the beginning of labour vs 13% at full cervical dilatation (P=0.006).

CONCLUSIONS

Bedside ultrasonographic antral CSA measurement is feasible in pregnant women during labour and easy to perform. The observed decrease in antral CSA during labour suggests that gastric motility is preserved under epidural anaesthesia. The procedure could be used to assess individual risk of gastric content aspiration during labour.

Pleth variability index is a weak predictor of fluid responsiveness in patients receiving norepinephrine

BACKGROUND

In patients receiving an infusion of norepinephrine, the relationship between the amplitude of the oximeter plethysmographic waveform and stroke volume may be variable and quality of the waveform might be reduced, compared with patients not receiving norepinephrine. We assessed the reliability of the pleth variability index (PVI), an automatic measurement of the respiratory variation of the plethysmographic waveform, for predicting fluid responsiveness in patients receiving norepinephrine infusions.

METHODS

We measured the response of cardiac index (transpulmonary thermodilution) to i.v. fluid administration in 42 critically ill patients receiving norepinephrine. Patients with arrhythmias, spontaneous breathing, tidal volume <8 ml kg(-1), and respiratory system compliance <30 ml cm H(2)O(-1) were excluded. Before fluid administration, we recorded the arterial pulse pressure variation (PPV) and pulse contour analysis-derived stroke volume variation (SVV, PiCCO2) and PVI (Masimo Radical-7).

RESULTS

In seven patients, the plethysmographic signal could not be obtained. Among the 35 remaining patients [mean SAPS II score=77 (sd=17)], i.v. fluid increased cardiac index ≥15% in 15 'responders'. A baseline PVI ≥16% predicted fluid responsiveness with a sensitivity of 47 (inter-quartile range=21-73)% and a specificity of 90 (68-99)%. The area under the receiver operating characteristic curve was significantly lower for PVI [0.68 (0.09)] than for PPV and SVV [0.93 (0.06) and 0.89 (0.07), respectively]. Considering all pairs of measurements, PVI was correlated with PPV (r(2)=0.27). The fluid-induced changes in PVI and PPV were not significantly correlated.

CONCLUSIONS

PVI was less reliable than PPV and SVV for predicting fluid responsiveness in critically ill patients receiving norepinephrine. In addition, PVI could not be measured in a significant proportion of patients. This suggests that PVI is not useful in patients receiving norepinephrine.

Plasma neutrophil gelatinase-associated lipocalin in kidney transplantation and early renal function prediction

BACKGROUND

This prospective observational study aimed to assess the relevance of serial postoperative plasma neutrophil gelatinase-associated lipocalin (NGAL) measurements on prediction of early renal transplant function.

METHODS

Plasma NGAL (pNGAL) was measured (Triage NGAL Test; Biosite Inc., Inverness Medical) in 41 patients scheduled for kidney transplantation from deceased or living donors, immediately before and after surgery, and at 12 hr, day 1, day 3, and day 7. A delayed graft function (DGF) was defined as the need for dialysis during the first week. The results were expressed as median (Q1, Q3).

RESULTS

Of the 41 consecutive patients enrolled, all had a high preoperative pNGAL level: 453 ng/mL (382, 595). Fifteen (36.6%) presented a DGF. In patients with DGF, pNGAL was significantly higher at 12 hr (571 [467, 634] vs. 242 [158, 299] ng/mL, P<0.0001) and at day 1 (466 [356, 627] vs. 165 [91, 248] ng/mL, P<0.0001). A pNGAL higher than 400 ng/mL 12 hr after transplantation predicted DGF with a sensitivity of 93.3%, a specificity of 88.5%, and an odds ratio of 63.2 (P=0.0004). This predictive performance was higher than for plasma creatinine.

CONCLUSIONS

pNGAL level early and accurately predicted DGF after renal transplantation. pNGAL measurements allowed monitoring of the renal function in this striking situation of ischemia-reperfusion aggression. Early identification of patients at risk of DGF, before graft lesions are consolidated, opens the field of a precise monitoring of renal injury and the impact of future protective therapeutics.

[Occupational asthma: retrospective study of a series of 144 cases]

The occupational origin of asthma is only found only late, from a diagnosis delay due to development. The aim of this work was to study the chronological characteristics of occupational asthma of different etiologies and to understand the occupational after-effects. A series of 144 cases were analysed (115 men and 29 women) who were seen in a consultation that specialised in occupational pathology, with the inclusion criteria those of the National Institute for Occupational Safety and Health (NIOSH). The analysis was based on: the causative allergen or work protocol; the role of atopy; length of the latency phase; length of symptom exposure; diagnosis delay; occupational consequences. Asthma from isocyanates and flour between them accounted for 62% in this series. These were followed by asthma from wood (8.3%) and persulphates (7.6%). The mean length of the latency period was 7.5 years and the mean diagnosis delay was 2.5 years. Clinical history of atopy and the existence of rhinitis were much more common for the "biological" than the "chemical" asthmas (respectively 69% and 95%, against 36% and 15%). Amongst the 64% of patients who benefited from complete removal of the allergen, 78.5% who were cured or improved, though for those who kept the same conditions of work there was a persistence or even aggravation of symptoms. In 74 cases a certificate of occupational illness was given to the patient.

[Respiratory allergies among symptomatic bakers and pastry cooks: initial results of a prevalence study]

A survey was carried out on respiratory symptoms and skin prick response to common allergens, storage mite and occupational allergens. Among 178 symptomatics bakers and pastry workers from small businesses in western France, only 65 people underwent skin prick and specific-IgE. 12 (18%) workers were skin positive to at least one common or occupational allergens. The more often skin positive were D. Ptero. mite 36 (57%); Alpha amylase 23 (35%); wheat flour 17 (26%); saccharomyces cerevisiae 16 (25%); Ephestia 15 (24%). The sensitivity of skin test was better than specific IgE for D. Ptero. Mite 36 (57%); and Alpha amylase 23 (35%). The sensitivity of specific IgE was better than skin test for wheat flour 26 (45%) and rye flour 23 (40%). Occurrence of skin positive to occupational allergen among symptomatics with rhinitis and asthma is much more frequent in workers with skin positive to common allergens (40/36) than in workers with skin negative (8/20). Atopy must be regarded as an important predisposing factor for skin sensitisation to occupational allergens. We conclude in the necessity of a standardised allergologic exploration to be done in symptomatics bakers.

[Respiratory allergies among bakers and pastry cooks: epidemiologic survey done in 1991 by the occupational physicians of the Loire-Atlantique]

The aim was to study the prevalence of respiratory allergy (rhinitis and asthma) in a population of bakers and pastrycooks. In 1991, 485 bakers and pastry cooks were examined by 27 work-physicians of Loire-Atlantic. The investigation was composed of a standardised questionnaire (signs of respiratory function, atopic history, smoking of tobacco ...), a clinical examination, and tests of respiratory function. An allergy assessment was made of all subjects with symptoms. 14.4% of subjects had rhinitis and 6.4% asthma. Development of these pathologies was clearly job-related for 2/3 of those with rhinitis and more than half of the asthmatics (55%). Occupational rhinitis and asthma were significantly more frequent in bakers than in pastrycooks and were linked to atopic history. Occupational asthma was associated with length of exposure to flour and with occupational rhinitis. In conclusion, these findings are comparable with or a little less than those that have been reported in occupational literature. They under-estimate the importance of the problem because of the occupational selection effect that is associated with these pathologies. Rhinitis and asthma are 1.5 to 3 time more common in bakers than in pastrycooks.

[Skin tests in the exploration of perianesthetic complications]

Adverse reactions in anesthesia are more and more frequent. The favoring factors are multiple but the physiopathology of these reactions are not right known: non specific histamine-release, complement activation is anaphylaxis can occur. Skin tests are an very important data for the diagnosis of these accidents. Forty patients and ten healthy subjects were tested with systematic research of a cross-reactivity for curare family; myorelaxants, fluid gelatin, dextran are the tests the most frequently positive. Cross reactivity for curare family is sure and sensibilization by some medicine is possible. Then the behavior of the data is looked at; the research of the favoring factors, the non utilization of some substances and prophylactic treatment are recommended.

Effects of diluents on skin tests

The role of diluents and preservatives on skin tests was examined in 41 allergic patients. The effect of glycerol in intradermal tests was studied. Concentrations of five percent glycerol were shown to induce a significant wheal which was not inhibited by clemastine fumarate, suggesting a direct toxic effect without the participation of histamine release. Twenty five Dermatophagoides pteronyssinus allergic patients were prick tested with standardized and lyophilized extracts reconstituted either in saline, 50% glycerol or human serum albumin. The wheal size induced by saline or HSA diluted extracts was very similar but greater than that elicited by extract dissolved in 50% glycerol. The correlation between prick tests induced by the three types of extracts tested was always significant.