[Pregnant women's use of tobacco and electronic cigarettes: A cross sectional survey]

OBJECTIVES

The article aims to describe tobacco and e-cigarette use among pregnant women: estimate the prevalence, identify the determinants and motivations of these behaviours.

METHODS

Cross-sectional, multicentre, descriptive observational study using self-administered questionnaires for pregnant women who visited ELENA healthcare centers in May 2021.

RESULTS

Of 223 patients, 38% were smokers before pregnancy and 16% continued to smoke during pregnancy. Nearly all the smokers (98%) declared that they had reduced or stopped their tobacco use, mostly without help. Young age, lack of professional activity, an unfavourable reaction to the announcement of the pregnancy, heavy smoking before the pregnancy and the presence of a smoker spouse were associated with smoking during pregnancy. Our study identified 10% of vapers before pregnancy and 7.2% during pregnancy. Of those who vaped during pregnancy, 81% were smokers before pregnancy. Most of them used a nicotine containing liquid and 38% of vapers combined smoking and e-cigarettes during pregnancy. There was no association between vaping during pregnancy and smoking cessation. A minority of women had received information about smoking during pregnancy.

CONCLUSIONS

The use of electronic cigarettes by pregnant women is a poorly-known reality in France, yet it concerns approximately 7% of the women in our sample. Prospective studies on larger numbers are needed to assess the prevalence of vaping among French pregnant women and its evolution during pregnancy.

[Relationship between vaping and smoking among 15-year-olds in high school. Results of a descriptive cross-sectional and monocentric observational study conducted in the metropolitan area of Saint-Étienne]

INTRODUCTION

The initiation of smoking among adolescents by vaping is a subject of controversy. This study focuses on the prevalence of electronic cigarette use among teenagers and its connection with the consumption of tobacco.

METHODS

A cross-sectional and monocentric study was conducted in the spring of 2018 and included 1435 students (15-16years old) from the metropolitan area of Saint-Étienne in France.

RESULTS

Nearly half of the adolescents experimented with e-cigarettes (50.30%) or tobacco (50.40%). Nearly a quarter are vapers (23.60%) or smokers (28.20%), with low daily use (3.65% for vaping and 9.40% for smoking). In regard to the link between smoking and vaping, 64.85% of adolescents are "non-smokers and non-vapers", 17.60% "smokers and vapers", 11.25% "smokers and non-vapers", and 6.30% "non-smokers and vapers".

DISCUSSION

The portrait-types of the vaper and the smoker are similar: boy rather than girl, educated in private school rather than public, and enrolled in a vocational rather than a general educational course. On one hand, the use of electronic cigarettes in non-smoking adolescents does not appear to be a major mode of entry into smoking or nicotine addiction. On the other hand, the use of electronic cigarettes among adolescent's smokers seems to have a beneficial effect on their smoking habit (stopping or reducing the consumption of tobacco).

Physical, morphological and chemical modification of Al-based nanofillers in by-products of incinerated nanocomposites and related biological outcome

The number of products containing nanomaterials is increasing this last ten years. Information and literature about the end-of-life of nanocomposites often remains partial and does not address the overall fate and transformations of nanoparticles that may affect biological responses. This paper underlines that the physico-chemical features of nanoparticles can be modified by the incineration process and the available toxicological data on pristine nanofillers might not be relevant to assess the modified nanoparticles included in soot. Combustion tests have been performed at lab-scale using a cone calorimeter modified to collect fumes (particulate matter and gas phase) and have been characterized using various techniques. Nanocomposites selected were poly(ethylene vinyl acetate) containing Al-based nanoparticles, i.e. boehmites or alumina. Evaluations of in vitro cytotoxicity responses on pristine nanofillers, soot and residual ash, show that safe boehmite nanoparticles, become toxic due to a chemical modification after incineration process.

[Bench-test evaluation of spacer devices for fluticasone delivery to infants]

INTRODUCTION

Use of a spacer device to optimize the delivery of fluticasone to infants with asthma is an important issue and clinicians require guidance around the choice of device. This in vitro study characterizes the particle size and the fluticasone delivery via 9 spacers.

METHODS

We used an in vitro infant nasal cast with two different inspiratory flow rates (50 and 100mL/s). Fluticasone particle size in the aerosol was evaluated by laser diffractometry and tracheal deposition by spectrophotometric assay.

RESULTS

Significant differences in particle size were observed between the 9 spacers (similar D50 but D90 from 5.65±0.65 to 8.80±1.35μm). A 75 % or higher respirable fraction was obtained for only 5 spacers. The 50mL/s flow rate lead to the best drug delivery. At this flow, OptiChamber^® (62±3 %) and Vortex^® (91±8.5 %) had a tracheal deposition over 50 % of the initial dose of fluticasone, although the 7 other spacers exhibited a fluticasone deposition less than 25 %.

DISCUSSION

This study shows a wide variation of drug delivery between the 9 spacers studied. We demonstrate that a low inspiratory flow and a spacer showing antistatic properties facilitate drug delivery.

Asymmetry of calmodulin revealed by peptide binding

The binding of amphiphilic peptides to calmodulin has been studied using fluorescence energy transfer techniques. Calmodulin has no tryptophan residues but possesses two tyrosines (at positions 99 and 138) in the C-terminal half of the protein. The peptides have a single tryptophan which serves as energy acceptor for the protein tyrosine fluorescence. For the binding of mastoparan or peptide Baa17, with a tryptophan at position 3, the observed quenching of the tyrosine fluorescence of over a factor of 2 corresponds to an average tyrosine-trytophan distance of less than 14 Å. These results indicate that the peptides binds preferentially with the tryptophan in the C-terminal half of the protein.

Size of submicrometric and nanometric particles affect cellular uptake and biological activity of macrophages in vitro

BACKGROUND

Micrometric and nanometric particles are increasingly used in different fields and may exhibit variable toxicity levels depending on their physicochemical characteristics. The aim of this study was to determine the impact of the size parameter on cellular uptake and biological activity, working with well-characterized fluorescent particles. We focused our attention on macrophages, the main target cells of the respiratory system responsible for the phagocytosis of the particles.

METHODS

FITC fluorescent silica particles of variable submicronic sizes (850, 500, 250 and 150 nm) but with similar surface coating (COOH) were tailored and physico-chemically characterized. These particles were then incubated with the RAW 264.7 macrophage cell line. After microscopic observations (SEM, TEM, confocal), a quantitative evaluation of the uptake was carried out. Fluorescence detected after a quenching with trypan blue allows us to distinguish and quantify entirely engulfed fluorescent particles from those just adhering to the cell membrane. Finally, these data were compared to the in vitro toxicity assessed in terms of cell damage, inflammation and oxidative stress (evaluated by LDH release, TNF-α and ROS production respectively).

RESULTS AND CONCLUSION

Particles were well characterized (fluorescence, size distribution, zeta potential, agglomeration and surface groups) and easily visualized after cellular uptake using confocal and electron microscopy. The number of internalized particles was precisely evaluated. Size was found to be an important parameter regarding particles uptake and in vitro toxicity but this latter strongly depends on the particles doses employed.

Does the RET variant G691S influence the features of sporadic medullary thyroid carcinoma?

OBJECTIVE

The RET (rearranged during transfection) proto-oncogene G691S variant is over-represented in the germline of patients with sporadic medullary thyroid carcinoma (sMTC) vs. normal controls but so far is not associated with any medical or pathological features of the tumour. The aim of our study was to assess the influence of this variant on the age of onset, clinical, biological and pathological features of sMTC.

DESIGN AND PATIENTS

One hundred patients with histologically proven MTC, for whom the germline genetic analysis of RET was negative and medical records were available, were included in the study.

RESULTS

Patients with the heterozygous GS variant or the homozygous SS variant (n = 36) were on average 8.0 years younger than patients with the wild-type GG variant (n = 64, mean age 43.9 vs. 51.9 years, P < 0.01). The former group did not differ from the wild-type group in terms of MTC size, prevalence of C-cell hyperplasia (CCH) or papillary thyroid carcinoma (PTC). However, the prevalence of an increased preoperative basal calcitonin (bCT) level (> 1000 pg/ml) was 2.75-fold higher in the patients with the GS or SS variant than in those with the wild-type variant (P < 0.001). The proportion of patients with lymph node metastases was also higher in the former group (P < 0.05). Multivariate analysis confirmed that the presence of the RET variant is independently associated with higher preoperative bCT values (P = 0.011).

CONCLUSIONS

Our data demonstrate that the RET G691S variant could modulate the age of onset of sMTC as demonstrated previously for familial tumours. Moreover, this variant is an independent predictor of a higher basal calcitonin synthesis rate in patients with sMTC.

Calcitonin levels do not decrease with weaning in chronic alcoholism

OBJECTIVE

Alcohol might increase calcitonin but this assertion is mainly based on the acute effect of the drug in small animals and humans. The aim of this study was to investigate the effect of chronic alcoholic intoxication on plasma calcitonin (CT) levels.

DESIGN

20 smoking male subjects admitted to be weaned from chronic daily alcohol consumption >100 g were included after informed consent. Blood was sampled upon admission (T0) and after 5 (T5) and 21 (T21) days of alcohol weaning to measure mean erythrocyte volume, gamma-glutamyltransferase (GGT), calcium, gastrin, and CT levels. The control group consisted of 30 male subjects with daily alcohol consumption <20 g.

MAIN OUTCOME

The characteristics of the alcohol group were as follows (mean +/- SD): age 41.2 +/- 13 years old; mean erythrocyte volume: 96.0 +/- 4.2 microm(3) (N: 85-95); calcium level: 94.7 +/- 3.7 mg/L (N: 85-105); gastrinemia: 59.3 +/- 14.9 ng/mL (N: <120). At T0 and T21, three alcoholic subjects had CT levels above 10 pg/mL, usually considered as the normal cut-off value. There was no correlation between CT and the different biochemical parameters at T0, T5, and T21. There was no difference between CT levels at the different stages in the alcohol group (T0: 6.4 +/- 3.6 pg/mL; T5: 6.5 +/- 5.3 pg/mL; T21: 8.4 +/- 5.6), although GGT significantly decreased with weaning duration (T0: 248 +/- 354 IU/L; T5: 211 +/- 290 IU/L; T21: 79 +/- 90 IU/L; ANOVA, p <0.05). But a significant difference was found between mean CT levels in the alcohol group and in the control group (3.1 +/- 0.7 pg/mL, p <0.0001).

CONCLUSIONS

This study suggests that mean CT levels of chronically alcoholic smoking male subjects are higher than those of an age- and sex-matched control group. However, most alcoholic patients exhibited CT levels <10 pg/mL. No decrease in CT levels was noted over a short period of alcohol weaning. As CT measurement is currently recommended in thyroid nodule assessment, this finding may be important to know how to decipher borderline values of CT.

Thyroid carcinomas involving follicular and parafollicular C cells: seventeen cases with characterization of RET oncogenic activation

Recent studies have focused on the occurrence of concomitant medullary-papillary thyroid carcinomas (MTC-PTC). The aims of this report were to compare the frequency of occult PTC in a population with MTC versus a control population that had undergone thyroidectomies and to check whether differences could be related to particular phenotype or genotype. To achieve these goals, we determined the frequency of occult PTC among patients operated for MTC (n = 82) or undergoing total thyroidectomy mainly for goiter and/or nodules (n = 7313) between 1994-2001. We then examined the clinical, histologic, and genetic characteristics (using a bio-chemical family inquiry and screening for RET germline mutations) of patients with associated PTC-MTC. Results show a significantly higher frequency of occult PTC in MTC (14.7%) than in total thyroidectomy (6.8%; p < 0.01). Seventeen cases of MTC or bilateral C-cell hyperplasia (CCH) and separate occult PTC were identified from 16 different families. Although common RET mutations providing evidence of familial forms of MTC were identified in only 3 of 16 families, clinical and histologic features usually seen in inherited forms of MTC such as young age of occurrence, bilateral CCH or associated case in family were found in 11 of the remaining 14 patients. In conclusion, results suggest that the association of MTC-PTC is not only a coincidence. Surprisingly, 11 of 17 MTC-PTC patients exhibited clinical, histologic, and/or family features usually encountered in familial forms despite the fact that no RET defect were present. This suggests the possible involvement of another gene or uncommon abnormality of RET gene.

A new generation of polymer nanoparticles for drug delivery

One of the main interests of using polymer nanoparticles as drug carrier systems is to control the delivery of the drugs including their biodistribution. During the last decade, it was clearly demonstrated that surface properties of nanoparticles were the key factor which determined the in vivo fate of such a carrier. Thus, the purpose of this work was to develop a new method which allows the easy fabrication of nanoparticles with versatile surface properties using polysaccharides. This preparation was based on the use of a redox radical polymerization reaction applied for the first time to the emulsion polymerization of alkylcyanoacrylates in aqueous continuous media. The dispersion of nanoparticles was very stable. The nanoparticle surfaces were coated with polysaccharides and their characteristics can be modulated by the type and the molecular weight of the polysaccharides used during the synthesis. Interestingly the biological properties of the polysaccharide immobilized on the nanoparticle surface can be preserved opening very interesting perspectives for such nanoparticles. This method also offers a new strategy for the design of modular biomimetic nanoparticles as drug carrier systems with multiple functions. One of the applications considered in this work was to use these nanoparticles coupled with haemoglobin as an oxygen carrier.

[Multiple endocrine neoplasias. Recent advances in clinical and genetic diagnosis]

PURPOSE

Multiple endocrine neoplasias (MEN) are autosomal dominant inherited syndromes characterized by the association of different glandular lesions in several members of the same kindred. The main clinical features of MEN 1 include primary hyperparathyroidism, pancreatic islet cell tumors and pituitary adenomas; less common features are adrenal adenomas, thymic and bronchial carcinoid tumors, lipomas and various cutaneous lesions. The MEN 2 syndromes (MEN 2A, MEN 2B and familial medullary thyroid carcinomas) are characterized by high penetrance of medullary thyroid carcinoma and differ in their variable expression of pheochromocytoma, hyperparathyroidism and other clinical features.

CURRENT KNOWLEDGE AND KEY POINTS

MEN 1 tumor suppressor gene encodes a nuclear protein, menin, which interacts with different regulation transcription factors. The MEN 2 syndromes are caused by germ-line mutations of the RET proto-oncogene, which encodes a transmembrane tyrosine kinase. Genetic testing for mutations in these 2 genes allows identification of individuals predisposed to the disease, early diagnosis, and clinical and therapeutic management.

FUTURE PROSPECTS AND PROJECTS

Fundamental approach will allow a best comprehension of physiopathogenic mechanisms of these disorders and the improvement of therapeutic management.

Clinical evaluation of a new sensitive calcitonin assay: study of specificity

BACKGROUND

Calcitonin (CT) is the most sensitive marker available for medullary thyroid carcinoma, but it lacks specificity. Procalcitonin is the precursor protein of calcitonin. Infections are known to be associated with elevations of procalcitonin. The aim of this study was to evaluate a new sensitive calcitonin assay in a large population and to study the assay specificity in two particular populations: patients with renal failure and patients hospitalized in intensive care units with a high procalcitonin level.

METHODS

Using two immunometric assays (A and B) to detect only mature calcitonin, we evaluated the calcitonin level in 488 sera (46 stimulation tests) from 340 subjects.

RESULTS

The clinical evaluation showed that the calcitonin concentrations obtained with the two assays were similar for all patients except those with high procalcitonin levels. Among the patients, 12% (n=13) had basal calcitonin concentrations greater than 10 pg/ml with method A and 25.7% (n=25) with kit B. No correlation was found between calcitonin and procalcitonin concentrations.

CONCLUSION

The new sensitive calcitonin assay tested is very efficient especially for the low concentrations. The cross-reaction for high procalcitonin levels exists and is variable according to the kits used. The procalcitonin evaluation can help the interpretation of ambiguous calcitonin levels.

Analysis of altered gene expression in rat soleus muscle atrophied by disuse

The present study involved a global analysis of genes whose expression was modified in rat soleus muscle atrophied after hindlimb suspension (HS). HS muscle unloading is a common model for muscle disuse that especially affects antigravity slow-twitch muscles such as the soleus muscle. A cDNA cloning strategy, based on suppression subtractive hybridization technology, led to the construction of two normalized soleus muscle cDNA libraries that were subtracted in opposite directions, i.e., atrophied soleus muscle cDNAs subtracted by control cDNAs and vice versa. Differential screening of the two libraries revealed 34 genes with altered expression in HS soleus muscle, including 11 novel cDNAs, in addition to the 2X and 2B myosin heavy chain genes expressed only in soleus muscles after HS. Gene up- and down-regulations were quantified by reverse Northern blot and classical Northern blot analysis. The 25 genes with known functions fell into seven important functional categories. The homogeneity of gene alterations within each category gave several clues for unraveling the interplay of cellular events implied in the muscle atrophy phenotype. In particular, our results indicate that modulations in slow- and fast-twitch-muscle component balance, the protein synthesis/secretion pathway, and the extracellular matrix/cytoskeleton axis are likely to be key molecular mechanisms of muscle atrophy. In addition, the cloning of novel cDNAs underlined the efficiency of the chosen technical approach and gave novel possibilities to further decipher the molecular mechanisms of muscle atrophy.

Effects of 14-day spaceflight on myosin heavy chain expression in biceps and triceps muscles of the rhesus monkey

In rats, changes in myosin expression are induced by the chronic elimination of weight-bearing activity, particularly in the postural muscles. This occurs during spaceflight and hindlimb suspension. Myosin heavy chain (MHC) changes affect fast and slow fiber types differently depending on muscle function. An increase in co-expression of different MHC within the same fiber will signal early changes in muscle fibers. In the rat soleus muscles, the spaceflight-induced increase in fast MHC expression appears to be essentially due to the enhanced or de novo synthesis of IID or IIX MHC. In response to microgravity, the expression of slow-type myosin decreases, while that of fast-type increases. There is scarce information concerning the effect of microgravity on rhesus monkeys (Macaca mulatta), especially on their upper limbs. We investigated the expression of MHC using an immunocytochemical approach to determine the nature and magnitude of the changes in biceps and triceps muscles of rhesus monkeys during the Bion 11 14-day mission.

Southeast Asian ovalocytosis in White persons

We describe two White persons, a girl and her mother, presenting with Southeast Asian ovalocytosis. The child was evaluated for scoliosis. The red cell indices were normal but the cell counter triggered an alarm due to a high fraction of hyperdense red cells. Blood smears showed ovalocytes and ovalostomatocytes. Red cells exhibited a total lack of deformability upon osmotic gradient ektacytometry performed immediately after blood drawing. Analysis of nucleic acids and proteins ascertained a 27 nucleotide deletion, resulting in the loss of amino acids 400 to 408, and the presence in cis of the Memphis I polymorphism. The sulfate transport was diminished by more than 50%. There was no acidosis. In vitro invasion of ovalocytes by Plasmodium falciparum was decreased. The mother presented with the same hematological picture. On the whole, the condition was Southeast Asian ovalocytosis in all respects. The present kindred had ancestors who had inhabited islands in the Southwestern Indian Ocean.

[Early therapeutic management of patients genetically predisposed to medullary thyroid cancer]

STUDY

The aim of our study was to study therapeutic results after thyroidectomy in patients positive for predictive genetic analysis and with preoperative calcitonin (CT) response to pentagastlin (Pg) < 150 pg/ml.

MATERIAL AND METHODS

36 patients (13 F, 23 M) were selected: 13 F-MTC from 8 families, 22 MEN 2A from 15 families and 1 MEN 2B. They were positive for direct RET mutation analysis. CT was assayed by immunoradiometric method before and after Pg. Pg test results before and after thyroidectomy, age at operation and histologic results were analysed.

RESULTS

Mean preoperative peak CT was 82.5 +/- 34.0 pg/ml (22-133): among these 36 patients preoperative basal and peak CT were normal in 16 and 2 patients respectively. F-MTC and MEN 2A patients were different according to their preoperative peak CT levels (58.1 +/- 24.0 vs 97.6 +/- 31.3) pg/ml, p < 0.01) and age at thyroidectomy (20.4 +/- 10.5 vs 11.6 +/- 7.6 years, p < 0.01 by Mann-Whitney test). Total thyroidectomy was performed in all patients at a mean age of 14.8 +/- 9.8 years (2.5-41.7) and was associated with lymph node dissection in 30 cases. The 2 F-MTC patients with normal preoperative peak CT levels had bilateral C-cell hyperplasia (CCH) associated with uni or bilateral micro-MTC. Other patients had uni or bilateral micro MTC except 4 who had isolated CCH without carcinoma. The age of two MEN-2A and 1 MEN 2B patients with micro-MTC ranged from 2.5 to 4.7 yr. Micro MTC was present in 100% of MEN-2A cases after the age of 10 yr. There were no lymph nodes metastases. During postoperative survey, the last PG tests (n = 33) were performed 27.5 months (1-92) after thyroidectomy: peak CT values were always < 10 pg/ml.

IN CONCLUSION

Thyroidectomy should be performed at a very young age in RET mutation carriers, regardless of the plasma CT values. This choice is justified in NEM-2A and NEM-2B patients but must be discussed in F-MTC families with less aggressive forms of the disease.

Effect of a 14-day spaceflight on dystrophin associated proteins complex in rat soleus muscle

One of the most obvious effects of hypokinesia and hypodynamia is muscular atrophy. Changes in myosin expression are induced by the chronic elimination of the weight-bearing activity, particularly in the postural muscles, which occur during spaceflight and hindlimb suspension. Other morphological changes, such as the remodeling of myotendinous junction, are also induced by this reduction in mechanical stress. Moreover, the transversal interface between the cytoskeleton and the extracellular matrix of the muscle fiber can also be modified by the functional demand imposed on muscle. Dystrophin and its associated proteins appear to be essential for the stability of this interface and the deletion of one of these proteins results in a pathological phenotype. Changes in their expression appears to be induced by muscle disuse. We have quantified the changes in the expression of dystrophin and associated proteins induced by a 14-day spaceflight.

Prognostic factors for survival and for biochemical cure in medullary thyroid carcinoma: results in 899 patients. The GETC Study Group. Groupe d'étude des tumeurs à calcitonine

BACKGROUND

Prognostic factors of sporadic or inherited medullary thyroid carcinoma (MTC) are still controversial and have been assessed in old and small series. A better knowledge of these factors would improve patient management.

OBJECTIVE

To evaluate factors involved in the prognosis of MTC in a large series of cases, using uni- and multivariate analysis.

DESIGN AND PATIENTS

Clinical, biological, surgical and epidemiological data on 899 MTC patients, diagnosed between 1952 and 1996, were collected by the French Calcitonin Tumors Study Group (GETC) with a standardized questionnaire, and processed in a national database.

MEASUREMENTS

Survival and biochemical cure (i.e. normal basal post-operative serum calcitonin levels) were analysed with Kaplan and Meier and log-rank test statistical procedures. Data are presented as adjusted rather than observed survival, to consider only patients who died of MTC. Cox's forward-stepping proportional hazard model was used to analyse factors with a significant influence on survival by univariate analysis.

RESULTS

Apart from the large proportion of familial forms (43%), the general characteristics of our population were similar to those in other studies: mean age at surgery = 43.4 years; sex ratio = 1 male/1.35 female; stage I = 20.8%; stage II = 21.2%; stage III = 46.5% and stage IV = 11.5%. 863 (96%) patients underwent surgery; 43% of operated patients were biochemically cured. Adjusted survival was 85.7 +/- 1.5% at 5 years and 78.4 +/- 2.1% at 10 years. Multivariate analysis showed that age and stage were independent predictive factors of survival. Gender, type of surgery, type of familial form were predictive only in univariate analysis. Biochemical cure predicts a survival rate of 97.7% at 10 years. Authentic recurrence, that is subsequent elevation of calcitonin (CT) after post-operative normalization, was found in 4.9%. In non-cured patients (57%), survival was still good: 80.2% (+/- 2.2%) and 70.3% (+/- 2.9%) at 5 and 10 years, respectively. Similarly, prediction of biochemical cure was solely dependent on stage.

CONCLUSION

Survival of these medullary thyroid carcinoma patients appears better than expected even in non-cured patients. Considering the strong impact of stage, the necessity for pre-operative diagnosis of MTC is obvious.

Risk and penetrance of primary hyperparathyroidism in multiple endocrine neoplasia type 2A families with mutations at codon 634 of the RET proto-oncogene. Groupe D'etude des Tumeurs à Calcitonine

Germline mutations of the RET proto-oncogene are responsible for multiple endocrine neoplasia type 2, including multiple endocrine type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma. The relationship between specific mutations and syndromic features has been established. In particular, the risk for pheochromocytoma and hyperparathyroidism (HPT) in MEN 2A patients is clearly associated with the presence of the RET mutation at a specific position, i.e. at codon 634. Also, a correlation between a specific mutation, C634R, and the development of HPT has been suggested but is still controversial. To further investigate the relationship between specific mutations of codon 634 and the development of HPT, we studied a population of 188 individuals, carrying mutations at codon 634, namely C634R (65 patients belonging to 10 families), C634Y (80 patients belonging to 11 families), or the less frequent codon 634 mutations [i.e. C634S, C634F, C634G, or C634W (43 patients belonging to 9 families)]. In this series of patients, we defined an overall HPT prevalence of 19.1% and found that this prevalence did not vary significantly, with respect to the nature of the mutation. However, irrespective of the particular mutation, the prevalence of HPT showed a high interfamilial variability. The statistical model that best fitted with the observed data was in favor of the heterogeneity of the risk for HPT, with 40% of the families showing an HPT risk of 34% and 60% of the families showing an HPT risk of 9%. In addition, our study clearly demonstrated that HPT could be an early component of the disease and provided the first estimate of age-specific and mutation-specific HPT penetrance in individuals with mutations of codon 634 of the RET proto-oncogene.

Heme-CO binding to tryptophan-containing calmodulin mutants

The binding of heme-CO to genetically engineered calmodulin containing a single tryptophan residue has been studied. A tryptophan residue was integrated at one of five positions: 26 or 62 of the N-terminal, 81 in the central helix, or 99 or 135 of the C-terminal. As for the wild type, the mutant calmodulins bind four molecules of heme-CO with an average affinity of 1 microM. (i) Homotropic effect. The quenching of the tryptophan fluorescence by energy transfer to the hemes indicates that there is no preference between the N- or C-terminal pockets for heme binding. The quenching is less than expected for a binomial distribution of four sites. This could indicate a lower energy transfer rate due to a specific orientation factor. The weak quenching as a function of the number of hemes bound may also reveal a cooperativity in the heme binding; the data can be simulated assuming two pairs of sites, where each pocket shows a cooperative binding for two hemes. (ii) Heterotropic effect. As observed for the wild type, addition of melittin does not displace the hemes from the mutant calmodulins; the affinity of heme-CO for the calmodulin.melittin complex is higher than that for calmodulin alone. The affinity of heme-CO for native calmodulin is also higher in the presence of trifluoperazine.

Picosecond geminate recombination of CO to the complexes calmodulin*heme-CO and calmodulin*heme-CO*melittin

Picosecond CO recombination kinetics have been measured after photodissociation of the artificial complexes calmodulin*heme-CO and calmodulin*heme-CO*melittin. These systems show an enhancement of the geminate fraction of kinetics relative to unbound heme-CO, due in part to fast geminate kinetics (tau=50ps for the initial phase), as well as a decrease in the rate of migration of CO away from the binding site. This indicates that calmodulin provides a complete pocket around the heme group. Rather than competing with the hemes for binding to calmodulin, the melittin seems to act as a cap to further enclose the hemes; melittin increases the affinity of calmodulin for heme-CO, but only weakly affects the CO recombination kinetics.

Protection by lazaroids of the erythrocyte (Ca2+, Mg2+)-ATPase against iron-induced inhibition

The calmodulin-stimulated (Ca2+, Mg2+)-ATPase (calmodulin-ATPase) of the erythrocyte membrane is susceptible to oxidative stress induced by heme and non-heme iron. There is a time-and concentration-dependent inhibition of the calmodulin-ATPase activity when the erythrocyte membranes are treated with either iron or hemin. In the present study, the calmodulin-ATPase has been used as a model system to evaluate the protective effects of a vitamin E analog (U83836E) and two 21-aminosteroids (U74500A and U74389G) against calmodulin-ATPase inhibition induced by iron and hemin. The drugs, lazaroids from Upjohn, can significantly protect the enzyme against iron-induced inhibition and also causes a decrease in the formation of thiobarbituric acid reactive species, with an IC50 of 0.4 microM for the drug U83836E and 4 microM for the drug U74500A. The 21-aminosteroid U74389G does not restore iron-inhibited calmodulin-ATPase activity under similar conditions. At higher concentrations (> 100 microM) all three drugs inhibit the calmodulin-ATPase activity. None of the drugs tested can restore hemin-inhibited calmodulin-ATPase activity.

Heme as an optical probe for studying the interactions between calmodulin and the Ca(2+)-ATPase of the human erythrocyte membrane

The heme group was used as an optical probe to study the interactions between calmodulin and its targets: the peptide melittin and the enzyme Ca(2+)-ATPase. As already reported, melittin when present in Tris buffer binds hemin-CN which quenches the tryptophan fluorescence. Addition of calmodulin restores the fluorescence significantly accompanied by a blue shift. We show here that the recovery of fluorescence is very slow and takes about 120 min to become constant. In a hydrophobic buffer, the fluorescence spectrum of melittin is already shifted with a peak at 335 nm and intensity almost 2-fold relative to a similar concentration of melittin in Tris buffer. The quenching of tryptophan fluorescence is lesser in this buffer and further addition of calmodulin fails to restore the fluorescence. This indicates the absence of binding of calmodulin to melittin in hydrophobic conditions. Under similar conditions of hydrophobicity, hemin-CN quenches about 35% of the tryptophan fluorescence of the Ca(2+)-ATPase. The subsequent addition of calmodulin restores about half of the quenched fluorescence. The interaction of calmodulin with the Ca(2+)-ATPase even under hydrophobic conditions suggests its high specificity for the enzyme which may be expected for a physiological target.

Sex steroid hormones in circulatory shock, sepsis syndrome, and septic shock

METHODS

Estrone (E1), estradiol (E2), testosterone (T), FSH, and LH levels were daily measured during a ten day period in 50 critically ill patients (38 men, 12 post-menopausal women). Patients were separated into four groups: A) no circulatory failure, no sepsis, B) sepsis syndrome without circulatory failure, C) circulatory failure without sepsis syndrome, D) septic shock. Results of hormonal measurements were compared 1) among the 4 groups, 2) between male and female patients, 3) between septic and nonseptic patients. The potential for the infusion of the vasoactive drug dobutamine to induce sex hormonal changes was documented in ten additional septic shock patients by measuring cortisol, E1, and T at base-line and after dobutamine infusion. Changes in active renin and plasma renin activity (PRA) were used as indirect witness of the dobutamine-induced beta 2-stimulation.

RESULTS

A dramatic increase in E1 and E2 levels was observed in women of groups B and D, and only in male patients of group D. In the septic patients, estrogen levels peaked at days 1 and 2 and trended to normal from day 6 after the onset of sepsis, while FSH and LH decreased. No difference was found between survivors and non-survivors. Whatever the group, male patients had low T levels throughout the study. Dobutamine induced a significant increase in active renin levels and a decrease in the regression slope between renin and PRA. Cortisol levels remained normal. No significant change in E1 and T was observed after dobutamine.

CONCLUSIONS

High estrogen levels were specifically observed in patients with sepsis and septic shock, either males or females. Decreased LH and FSH levels were consistent with the negative feed-back effect of high estrogen levels on pituitary secretion. Circulating T levels were decreased in all male patients. We found no correlation between sequential estrogen levels and outcome. These levels were not modified by a dobutamine-induced beta-2 stimulation.

Heme binding to calmodulin, troponin C, and parvalbumin, as a probe of calcium-dependent conformational changes

Heme-CO binds to the active (calcium-bound) form of calmodulin (CaM), but not to the inactive form. Despite a similarity in structure of another calcium-binding protein, skeletal muscle troponin C, both the affinity and the spectral red-shift of the absorption of the heme group are greatly decreased for troponin C relative to calmodulin. Parvalbumin, another calcium-binding protein, shows a twofold greater affinity for heme-CO relative to CaM. Unlike calmodulin and troponin C, the affinity of parvalbumin for heme-CO is even greater in the absence of calcium. The affinity of the tryptic and thrombic fragments of CaM for heme-CO are decreased relative to the entire calmodulin. The binding of heme-CO is specific as demonstrated by the discrimination of the calmodulin, troponin C, and parvalbumin pockets. The interaction of heme-CO with active (calcium-bound) CaM is rapid (ms) as determined by stopped flow measurements. No difference in kinetics was observed for mixing inactive (calcium free) CaM with a solution of [heme-CO plus calcium], indicating that the calcium-binding step and subsequent change in protein conformation are rapid.

Interaction of heme with amphiphilic peptides: use of hemin-CN to probe the interaction of calmodulin with its target peptides

The interaction of heme with several amphiphilic peptides has been studied by absorption and fluorescence spectroscopy. The binding can be followed by the changes in the absorption spectrum of the heme group or by the decrease in the peptide tryptophan fluorescence due to energy transfer to the heme. Despite their small size, ranging from 26 residues for melittin to 14 for mastoporan, a high affinity for heme-CO and hemin-CN (Kd < 100 nM) may be observed. Spectral shifts in the absorption peaks and appreciable geminate recombination after photodissociation of CO from the complex peptide-heme-CO suggest the formation of a heme pocket, as for the natural heme proteins.

APPLICATION

hemin-CN can be used as a probe for the interaction of calmodulin with these target peptides. Amphiphilic peptides such as melittin bind to calmodulin with a high (nM) affinity. While both the peptide and calcium-bound calmodulin bind heme-CO, only the peptide binds hemin-CN. These interactions permit studies of the competition between hemin-CN and calmodulin for binding to the peptide: while hemin-CN quenches the melittin tryptophan fluorescence, addition of calmodulin to the [melittin*hemin-CN] complex displaces the hemin-CN and the melittin tryptophan fluorescence is recovered.

Optical binary phase-only filters for circular harmonic correlations

In our previous paper we proposed using successively binary cosine and sine filters and combining the correlation intensities for rotation-invariant phase-only circular harmonic correlation. This paper presents an alternative method that uses a single filter. We present theory and optical and computer experimental results to show that, with a spatial frequency carrier, the binary phase-only filter [1, -1] and the binary filter [1, 0] yield the impulse response of a continuous phase-only filter. Compared with conventional computer-generated holographic filters, the binary phase-only filter and the binary filter have no representation-related error, require a minimum space-bandwidth product, and may be implemented in a spatial light modulator.

Hypothyroidism following combined treatment for hypopharyngeal and laryngeal carcinoma

The development of hypothyroidism following combined treatment for pharyngeal and laryngeal cancer has received little attention in the literature. We prospectively studied 32 patients over 4 years to determine the incidence of such hypothyroidism and to examine the effect of hemithyroidectomy associated with a combined treatment modality. All patients were men with pharyngeal or laryngeal squamous cell carcinomas and no prior history of thyroid disease. Treatment consisted of radical surgery (30 of 32 patients), followed by postoperative radiotherapy (31 patients). The results of thyroid function tests (free triiodothyronine, free thyroxine, and thyroid-stimulating hormone [TSH]) were all normal preoperatively; tests were repeated every 3 months after treatment. Elevation of TSH values in two successive blood samples was required to make a diagnosis of hypothyroidism. Of 12 patients who underwent hemithyroidectomy as part of total pharyngolaryngectomy and postoperative radiotherapy, 7 became hypothyroid a mean of 6 months after treatment. Twenty patients had similar combined treatment but without thyroid resection. Hypothyroidism developed a mean of 10 months after treatment in only four patients in this group (p less than 0.05). We conclude that hypothyroidism frequently develops following combined treatment for pharyngeal and laryngeal cancer even when thyroid resection has not been performed. Patients should be evaluated postoperatively and carefully monitored by means of serial thyroid function tests.

Inhibition of the erythrocyte (Ca2+ + Mg2+)-ATPase by nonheme iron

The erythrocyte calmodulin-stimulated (Ca2+ + Mg2+)-ATPase (CaM-ATPase), an integral membrane protein, is inhibited in different types of congenital hemolytic anemias for which oxidative processes appear as a common feature. The oxidation of hemoglobin and its degradation lead to the accumulation of ferric heme (hemin) and nonheme iron in the red cell. We have shown previously that hemin inhibits the activity of the enzyme of normal erythrocyte (Leclerc et al. (1988) Biochim. Biophys. Acta, 946, 49-56) involving an oxidation of thiol groups. The present study demonstrates that nonheme iron also inhibits the CaM-ATPase activity. In contrast with hemin, the inhibition of the enzyme induced by the nonheme treatment is prevented by butylated hydroxytoluene, a protecting agent of unsaturated phospholipid peroxidations, while dithiothreitol, a reducing agent of protein disulfide bridges, does not restore the activity of the enzyme. We conclude that nonheme iron inhibits the enzyme at least in part, through the peroxidation of phospholipids of the membrane bilayer.

Heme-CO as a probe of the conformational state of calmodulin

The interaction of heme-CO with calmodulin, in the presence of calcium, leads to a complex of four heme-CO molecules per protein. No interaction was observed in the absence of calcium. The binding of heme-CO to calmodulin was monitored by the shift in the Soret absorption band from 407 to 420 nm (bound form); the four sites are not spectrally identical. The ligand CO can be photodissociated from the calmodulin-heme-CO complex and the biomolecular recombination kinetics also indicate a heterogeneous mixture. The complex does not bind oxygen reversibly. As calmodulin has only one histidine, the hemes are apparently not bound by the iron atom as in hemoglobin, but are probably loosely associated (Kd = 0.5 microM) in hydrophobic pockets which apparently open when the protein is activated by calcium.

Flash photolysis of the serum albumin-heme-CO complex

Protoheme-CO in aqueous solution does not exhibit a geminate ligand recombination reaction. Addition of a protein, either globin or serum albumin, to which heme binds strongly, leads to an observable geminate reaction in aqueous solution. The bimolecular kinetic data for the albumin-heme-CO complex show two stable components, one heme-like in rate and difference spectrum, and one hemoglobin-like. The geminate reaction correlates spectrally with the hemoglobin-like component.

Rotation invariant phase-only and binary phase-only correlation

Phase-only circular harmonic filters and binary phase-only circular harmonic filters are proposed. Both filters have full rotation invariance and excellent performance for discrimination between objects and against background noise. Their properties have been studied and implemented for computer applications. The binary filters are appropriate for real-time applications using spatial light modulators.

[Postpartum thyroiditis. 31 cases]

Postpartum thyroiditis. 31 cases. Between 1977 and 1986, 29 women consulted in three internal medicine and endocrinology departments for clinical disorders which could be ascribed to 31 episodes of thyroiditis developed within 9 months of giving birth. Thyroiditis was diagnosed clinically on the basis of acute diffuse (11 cases) or nodular (7 cases) goitre formation, signs of dysthyroidism (16 cases) revealed by menstrual disturbances and/or galactorrhoea (11 cases). A thyrotoxic episode was observed in 9 patients; it was either without sequelae (5 cases) of followed by transient hypothyroidism (4 cases). In other patients transient hypothyroidism was observed in 11 cases and permanent hypothyroidism in 5 cases. Six patients showed no sign of dysthyroidism, and the diagnosis was made by immunological, cytological and/or histological examination of the thyroid gland. Circulating anti-thyroid antibodies were present in two-thirds of the patients. The results of radioisotope scanning varied according to the stage of the disease. In these patients, only the absence of goitre was predictive, in 4 out of 5 cases, of subsequent permanent hypothyroidism; in all other patients the prognosis was highly favourable, even without specific treatment.

Muscarinic cholinergic induced secretin subsensitivity in rat isolated pancreatic acini. Effects on amylase release, cyclic adenosine monophosphate and inositol phosphate formation

In this study, dispersed rat pancreatic acini exhibited secretin subsensitivity in their capacity to release amylase after preexposure to increasing concentrations of the muscarinic cholinergic agonist carbamylcholine. The present study also explores the potential mechanisms involved in this cellular desensitization phenomenon. Secretin subsensitivity of pancreatic acini pre-exposed to 10(-4) M carbamylcholine was observed only at secretin concentrations above 10(-8) M. The desensitized cells had not recovered 3 h after the cholinergic agonist exposure. In these acini, the adenylate cyclase pathway remained unaltered because cholera toxin, forskolin, and 8-Br-cAMP still induced weak, but normal, amylase release when compared with control acini. In vivo administration of pertussis toxin failed to protect the dispersed pancreatic acini against carbamylcholine-induced secretin subsensitivity. Moreover, cAMP production by these acini in response to secretin, cholera toxin, and forskolin was similar to that observed in control acini. Secretin stimulation of inositol phosphate (InsP1, InsP2, InsP3) production after carbamylcholine pre-exposure remained equivalent to that observed in acini that had never been exposed to the cholinergic agonist. Thus, after muscarinic cholinergic agonist exposure, pancreatic acini showed secretin subsensitivity in their capacity to release enzyme. This phenomenon appears to result from modifications at post-second messenger loci.

Inhibition of membrane erythrocyte (Ca2+ + Mg2+)-ATPase by hemin

Red blood cell lysis is a common symptom following severe or prolonged oxidative stress. Oxidative processes occur commonly in sickle cells, probably mediated through denatured hemoglobin and the accumulation of ferric hemes in the membranes. Calmodulin-stimulated (Ca2+ + Mg2+)-ATPase from sickle red cell membranes is partially inactivated (Leclerc et al. (1987) Biochim. Biophys. Acta 897, 33-40). In this study (Ca2+ + Mg2+)-ATPase activity from normal adult erythrocyte membranes was measured in the presence of hemin. We report a time- and concentration-dependent inhibition of the activity of the enzyme by hemin due to a decrease in the maximum velocity. Only a mild inhibitory effect was observed in the presence of iron-free protoporphyrin IX, indicating the catalytic influence of the iron. Experiments carried out with hemin (ferric iron) liganded with imidazole or with reduced protoheme (ferrous iron) liganded with carbon monoxide, demonstrated that the inhibition requires that hemin be capable of binding additional ligands. The inhibition was not influenced by the absence of oxygen but was prevented by addition of bovine serum albumin. Addition of butylated hydroxytoluene, a protective agent of lipid peroxidation, failed to prevent the inhibition of calmodulin-stimulated (Ca2+ + Mg2+)-ATPase. As dithiothreitol partially restores the enzyme activity, we postulated that hemin interacts with the thiol groups of the enzyme.

[Hyperreninemic hypoaldosteronism syndrome induced by plasma exchange]

The study was designed to measure sequential changes in plasma renin activity, aldosterone, angiotensin-converting enzyme activity and ionograms, prior to, and after therapeutic plasma exchange. Each measurement was repeated before and after stimulation of renin activity induced by furosemide. The results showed that plasma exchange induces a syndrome of hyperreninemic hypoaldosteronism associated with a depletion in angiotensin-converting enzyme activity which might account for the dissociation between plasma renin activity and aldosterone.

Decrease of angiotensin-converting enzyme activity after plasma exchange

We measured sequential changes in serum angiotensin-converting enzyme (ACE) in 12 ICU patients undergoing plasma exchange (PE) with plasma substitutes (albumin-Polygelin). A dramatic decrease in serum ACE activity was observed after each of the 51 PE procedures. Repeated PE procedures resulted in almost a total depletion of serum ACE, which returned to normal ranges in 4 to 10 days. No ACE change was observed during hemodialysis or hemofiltration. ACE activity increased after PE with fresh frozen plasma replacement. ACE changes were compared with IgG, antithrombin III, and fibronectin changes. Extraction ratio comparisons were consistent, with a loss in removed plasma accounting for 50% to 70% of the observed ACE decrease. Plasma zinc levels were not modified after PE. Mixing experiments with increasing volumes of plasma substitutes showed ACE inhibition by Polygelin. In vivo infusion of Polygelin had the same effect. The renin-induced aldosterone response studied in six exchanged patients was consistent with a relative hyperreninemic hypoaldosteronism after repeated PE. These findings may be of clinical relevance during acute hypovolemia and dehydration after PE or Polygelin infusion and in patients with impaired lung endothelial function.

Activity of cyclic GMP-dependent protein kinase in aortae from spontaneously hypertensive rats

It has been suggested that various agents induce relaxation of vascular smooth muscles through guanosine 3',5'-cyclic monophosphate (cGMP) and cGMP-dependent protein kinase (cGMP-PK). In this work, the activity of cGMP-PK was studied in the 30,000 g supernatant from aortae of 4, 6, 8 and 12-week-old spontaneously hypertensive (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats and also of 4 and 12-week-old normotensive Wistar (W) and Sprague Dawley (SD) rats. At 4 weeks of age, both basal and cGMP-stimulated activity were not different in SHR and WKY rats. Nevertheless, a greater basal activity was measured in W (+50%) and SD (+20%) rats than in SHR, while no difference was observed between stimulated activities. In contrast with observations in the three normotensive rat strains, cGMP-PK activity did not decrease in the aortae supernatant of SHR rats aged 4-12 weeks. This resulted in mean increases of 45 and 30% in the basal and the cGMP-stimulated activity, respectively, in the 12-week-old SHR rats. The abnormal evolution of cGMP-PK activity in the hypertensive strain was already detectable at 4-6 weeks of age. In apparent agreement with observations on protein kinase activity, cGMP binding activity attributable to cGMP-PK was 25% greater in 12-week-old hypertensive rats compared with age-matched WKY rats. These results indicate that in aortae of SHR rats, control of cGMP-PK activity is abnormal early in life.

The calmodulin-stimulated (Ca2+ + Mg2+)-ATPase in hemoglobin S erythrocyte membranes: effects of sickling and oxidative agents

A decrease in the reactivity of erythrocyte membrane (Ca2+ + Mg2+)-ATPase to calmodulin stimulation has been observed in aging red cells and in various types of hemolytic anemias, particularly in sickle red cell membranes. Unlike the aging process, the defect in the (Ca2+ + Mg2+)-ATPase from SS red blood cells is not secondary to a decrease in calmodulin activity and is already present in the least dense SS red blood cells separated on a discontinuous density gradient. Deoxygenated AS red cells were forced to sickle by lowering the pH, raising the osmolarity of the buffer (sickling pulse). Under these conditions an inhibition of the calmodulin-stimulated enzyme was observed only if several cycles of oxygenation/deoxygenation were applied. No alteration of the enzyme could be detected after submitting AS red blood cells to other conditions or in AA red blood cells submitted to the same treatments. This suggests that oxidative processes are involved in the alterations of the (Ca2+ + Mg2+)-ATPase activity. Treatment of membranes from AA erythrocytes by thiol group reagents and malondialdehyde, a by-product of auto-oxidation of membrane unsaturated lipids and a cross-linking agent of cytoskeletal proteins, led to a partial inhibition of the calmodulin-stimulated (Ca2+ + Mg2+)-ATPase. We postulate that the hyperproduction of free radicals described in the SS red blood cells and involved in the destabilization of the membrane may be also responsible for the (Ca2+ + Mg2+)-ATPase failure.

The influence of nitroheterocyclic radiosensitizers on the membrane of red blood cells

Nitroimidazole compounds are effective radiosensitizers, but neurotoxic side effects prevent their clinical use. Studying the effect of misonidazole, metronidazole and two of its derivatives, 4.5-NO2-METRO and 4-NO2-METRO, on red blood cell, it was recently demonstrated that these compounds inhibit the red cell membrane (Na+-K+) ATPase and decrease the fluidity of the membrane bilayer. In order to extend these observations and to achieve a more complete interpretation, four additional investigations were selected: the (Ca++-Mg++)ATPase activity, the anion channel (band 3 protein) kinetics, the susceptibility of the phospholipids to peroxidation, and their influence on the concentration of reduced glutathione (GSH). The activity of the (Ca++-Mg++)ATPase and its stimulation by calmodulin were decreased by all four drugs, but the anion transport kinetics were unaltered. No lipid peroxidation could be detected, as estimated by the production of malonyldialdehyde. The red cell GSH was depleted by 4.5-NO2-METRO, probably due to the formation of a complex between GSH and the drugs [Varghese 1983]. The mechanism of the inhibition of the ATPases is not yet clearly apparent; it is presently sought in a direct interaction of the drugs with some thiol reactive groups of the ATPases.