Substantiation of an artificial saliva formulated for use in a masticatory apparatus

The aim of this work was to substantiate artificial saliva prepared for use in a masticator apparatus. Mastication's goal is to produce a viscous and plastic food bolus where these properties authorize a safe swallow. Apart from its biochemical contribution, saliva is mainly used in this kind of apparatus to provide a viscous component to the bolus. Artificial saliva was prepared with water and minerals, and completed with mucin and amylase. Different physico-chemical conditions were applied and the resultant viscosity was compared to that of human saliva. Mechanically- or chemically-stimulated salivas of ten healthy subjects were collected. Viscosity was measured with a capillary viscometer in response to changes in measurement's temperature, air exposure or pH. The effects of circadian saliva collection and the stimulation type on viscosity of human saliva were also studied. Viscosity of artificial and human salivas was comparable. An increase in the measurement's temperature or a 30 min-exposure of saliva to air led to a significant decrease in viscosity of both types of saliva. Amylase in artificial saliva did not change viscosity. The viscosity of human saliva displayed important subject variability as well as a dependence on the stimulation type of saliva production. This work allowed a useful evaluation of the formulated artificial saliva. It exhibited similar viscosity as the natural saliva in response to different methodological conditions. Therefore the proposed artificial saliva satisfies the major requirement of viscosity for a use in the masticator apparatus designed to prepare a food bolus.

Feature Selection with Conjunctions of Decision Stumps and Learning from Microarray Data

One of the objectives of designing feature selection learning algorithms is to obtain classifiers that depend on a small number of attributes and have verifiable future performance guarantees. There are few, if any, approaches that successfully address the two goals simultaneously. To the best of our knowledge, such algorithms that give theoretical bounds on the future performance have not been proposed so far in the context of the classification of gene expression data. In this work, we investigate the premise of learning a conjunction (or disjunction) of decision stumps in Occam's Razor, Sample Compression, and PAC-Bayes learning settings for identifying a small subset of attributes that can be used to perform reliable classification tasks. We apply the proposed approaches for gene identification from DNA microarray data and compare our results to those of the well-known successful approaches proposed for the task. We show that our algorithm not only finds hypotheses with a much smaller number of genes while giving competitive classification accuracy but also having tight risk guarantees on future performance, unlike other approaches. The proposed approaches are general and extensible in terms of both designing novel algorithms and application to other domains.

Changes in pulse pressure, heart rate and the pulse pressure x heart rate product during squatting in Type 1 diabetes according to age

AIMS

We assessed changes in pulse pressure and heart rate during a squatting test, as indirect markers of arterial stiffness and cardiovascular autonomic neuropathy, respectively, according to age and sex in patients with Type 1 diabetes mellitus.

METHODS

We evaluated 160 diabetic patients, divided into four groups of 20 men and 20 women according to age (G1, 20-30 years old; G2, 31-40 years old; G3, 41-50 years old; and G4, 51-60 years old), and 160 non-diabetic matched control subjects. Each subject underwent a 3 min posture test (standing-squatting-standing) with continuous measurement of arterial blood pressure and heart rate by a Finapres device. Overall values throughout the test, baseline levels in initial standing position and squatting-induced changes in pulse pressure, heart rate and the pulse pressure x heart rate product were compared between diabetic patients and healthy control subjects.

RESULTS

In the standing position, a greater increase in pulse pressure and lower reduction in heart rate with age led to a significantly higher pulse pressure x heart rate product in diabetic patients compared with control subjects. In the squatting position, a more marked pulse pressure increase in the absence of appropriate reduction in heart rate resulted in a greater rise in the pulse pressure x heart rate product in diabetic patients than in healthy subjects. No major differences were noted between the sexes, with the exception of a stronger relationship between pulse pressure and age in the female population with diabetes. Squatting-derived indices of cardiovascular autonomic neuropathy were also noted with increasing age in diabetic patients.

CONCLUSIONS

The marked increase in the pulse pressure x heart rate product ('pulsatile stress') according to age, combined with cardiovascular autonomic neuropathy, may contribute to the higher cardiovascular risk of patients with Type 1 diabetes.

Pancreatic hypoplasia presenting with neonatal diabetes mellitus in association with congenital heart defect and developmental delay

Congenital pancreatic hypoplasia is a rare cause of neonatal diabetes. We report on a series of three patients with pancreatic agenesis and congenital heart defects. All had abdominal scan evidence of pancreatic agenesis. In addition, Patient 1 had a ventricular septal defect, patent ductus arteriosus and pulmonary artery stenosis; Patient 2 had a truncus arteriosus and Patient 3 had tetralogy of Fallot. Two of the three patients have developmental delay. All three patients were isolated cases within the family. Investigations included sequencing of GCK, ABCC8, IPF1, NEUROD1, PTF1A, HNF1B, INS, ISL1, NGN3, HHEX, G6PC2, TCF7L2, SOX4, FOXP3 (Patients 1 and 2), GATA4 and KCNJ11 genes (all three patients), but no mutations were found. Genetic investigation to exclude paternal UPD 6, methylation aberrations and duplications of 6q24 was also negative in all three. 22q11 deletion was excluded in all three patients. Array CGH in Patient (1) showed a approximately 250 kb, paternally inherited duplication of chromosome 12q [arr cgh 12q24.33 (B35:CHR12:131808577-132057649++) pat], not found in the other two patients. Permanent neonatal diabetes mellitus due to pancreatic hypoplasia with congenital heart defects has been reported before and may represent a distinct condition. We discuss this rare association and review previously reported literature.

Pulse pressure and cardiovascular autonomic neuropathy according to duration of type 1 diabetes

BACKGROUND

To evaluate changes in pulse pressure (PP) and markers of cardiovascular autonomic neuropathy (CAN) according to duration of type 1 diabetes mellitus (T1DM).

METHODS

This cross-sectional controlled study evaluated 159 diabetic patients during a 3-min posture test (standing-squatting-standing) with continuous measurement of systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure by a Finapres device. Arterial stiffness was indirectly assessed by PP and the slope of PP as a function of MBP calculated during the whole 3-min test. CAN was assessed by the expiration/inspiration pulse interval ratio (E/I R-R ratio) during deep breathing and by three indices measured during the squatting test. Patients were divided into four groups according to diabetes duration (<10 years, 11-20 years, 21-30 years and > 30 years from group 1 to group 4, respectively) and compared with age-matched non-diabetic subjects.

RESULTS

PP progressively increased (p < 0.0001) and PP/MBP decreased (p < 0.0005) according to T1DM duration, whereas these parameters remained almost unchanged in age-matched control subjects. E/I ratio (p < 0.0001) and baroreflex gain (p < 0.0005) progressively decreased with T1DM duration. The parasympathetic index (squatting test vagal ratio-SqTv) significantly increased (p < 0.0001), whereas the sympathetic index (squatting test sympathetic ratio-SqTs) only tended to decrease (p = 0.12) according to diabetes duration. No such changes in CAN indices were observed in the non-diabetic population.

CONCLUSIONS

PP increased according to T1DM duration in an age range where PP remained almost stable in controls, in agreement with accelerated arterial stiffening due to chronic hyperglycaemia. The baroreflex gain decreased and other indices of CAN also deteriorated with diabetes duration, more so indices reflecting parasympathetic rather than sympathetic dysfunction.

Comparing immunogenicities of tumor-specific antigens administered as therapeutic vaccines in metastatic melanoma patients

3003

Background: Therapeutic vaccination of metastatic melanoma patients with detectable disease is followed by some tumor regression in only about 10% of the patients, with no clear difference observed between studies carried out with various tumor-specific antigens and vaccination modalities. For antigenic peptide MAGE-A3168–176, presented by HLA-A1 molecules and administered as peptide alone or recombinant ALVAC poxvirus, anti-vaccine T lymphocyte (CTL) responses have been observed in no progressor patient and in only half of the regressors, suggesting a poor immunogenicity of these vaccines. Methods and Results: We compiled anti-vaccine CTL responses measured in the blood of 202 metastatic melanoma patients vaccinated with various associations of 10 different tumor antigens administered as peptides, alone or with adjuvant, recombinant ALVAC poxvirus, or peptide-pulsed dendritic cells. Blood lymphocytes collected before and after vaccination were all analyzed with the same method involving in vitro restimulation in limiting dilution condition followed by labeling with tetramers for each antigen. A CTL response was deemed to have occurred if the CTL frequency increased by at least 10 times, and if the pre-vaccination frequency was lower than 2 x 10-6 of the CD8 cells. No responses were detected against peptides MAGE- A4230–239 (0/26) and MAGE-C2336–344 (0/22). Some were observed against MAGE-A3168–176 (11/81), MAGE-A1278–286 (2/22), MAGE-A3112–120 (2/55), and MAGE-A10254–262 (2/35). Responses were frequently found against NY-ESO-1157–165 (10/19), GnTVVLPDVFIRC (18/73), gp100209–217 (21/33), or Tyrosinase369–377 (11/59). For the latter four antigens, there was no correlation between the occurrence of CTL responses and that of tumor regressions. Neither did we find a correlation between the CTL responses and the expression of the antigen-encoding genes in pre- vaccination tumor samples. Conclusions: These results suggest that some of the antigenic peptides that are commonly used in melanoma vaccines are more immunogenic than others but do not induce more tumor regressions. Therefore, inducing strong CTL responses against these immunogenic peptides is probably not the most appropriate endpoint of future vaccine trials.

No significant financial relationships to disclose.

[Arterial pulse pressure in relation to the duration of type 1 diabetes: a cross-sectional controlled study]

Diabetes mellitus and arterial pulse pressure (PP) are two independent cardiovascular risk factors. This cross-sectional study investigated the influence of diabetes duration on PP in type 1 diabetic patients without any cardiovascular disease. PP was measured continuously during 3 minutes (active orthostatic test: 1 min standing--1 min squatting--1 min standing) using a fingertip plethysmograph (Finapres) in 159 type 1 diabetic patients aged 20-60 yrs. They were divided into 4 groups according to diabetes duration: (1) G1 : <10 yrs (n=39); G2: 11-20 yrs (n=45); G3: 21-30 yrs (n=57); and G4: >30 yrs (n=18). In order to separate the effects of age from the effects of diabetes duration, diabetic patients were compared to age- and sex-matched non diabetic controls. PP (expressed in mmHg; mean +/- SD) was higher in men than in women in both diabetic (58 +/- 15 vs. 50 +/- 14; p = 0.001) and non diabetic subjects (55 +/- 14 vs. 47 +/- 12; p = 0.001). Overall PP was higher in diabetic than in non diabetic individuals (54 +/- 15 vs. 50 +/- 13; p = 0.025). PP progressively increased according to diabetes duration: 47 +/- 16 vs. 51 +/- 13 vs. 59 +/- 14 vs. 62 +/- 12, from G1 to G4 respectively; p < 0.0001. Such an increase was not observed in age-matched non diabetic subjects: 50 +/- 11 vs. 52 +/- 12 vs. 49 +/- 14 vs. 52 +/- 18, from G1 to G4, respectively; NS. PP was higher in squatting than in standing position in non diabetic subjects (52 +/- 16 vs. 47 +/- 13; p < 0.0001) and even more in diabetic patients (59 +/- 17 vs. 50 +/- 14; p < 0.0001). Overall, PP difference between diabetic and non diabetic individuals was not significant in standing position (50 +/- 14 vs. 47 +/- 13; NS) although it became highly significant in squatting position (59 +/- 17 vs. 52 +/- 16; p = 0.0005). The squatting-standing difference in PP markedly increased with diabetes duration: 69 +/- 14 during squatting vs. 50 +/- 18 during standing in G4 compared to respectively 50 +/- 17 vs. 44 +/- 15 in G1 diabetic patients. Finally, PP was similar (NS) in diabetic patients with HbA1c < 8% (54 +/- 14) or > or =8% (55 +/- 16), with (57 +/- 17) or without (54 +/- 14) microalbuminuria, treated (56 +/- 14) or not (54 +/- 15) by inhibitors of the renin-angiotensin system. In conclusion, PP progressively increased with the duration of type 1 diabetes, independently of age. Such increase was more marked in squatting than in standing position. The role of such PP rise in the increased cardiovascular risk of patients with type 1 diabetes, although suspected in the recent EURODIAB Prospective Complications Study, deserves further investigation.

Tuning formulation of multipeptide vaccination for melanoma patients at high risk of relapse

18014

Background: Vaccination with MAGE peptides is followed by tumor regression in 10–20% of metastatic melanoma patients with detectable disease, mostly those with only SC or lymph node metastases. Anti-vaccine cytolytic T lymphocyte (CTL) responses have been observed in about 50% of the regressor patients, suggesting that these vaccines were poorly immunogenic. Recent reports have documented convincing CTL responses in patients vaccinated with peptides administered in a water-in-oil emulsion with Montanide, a clinical grade incomplete Freund’s adjuvant. After SC injection, this vaccine stimulates a local inflammation which could help to the recruitment of peptide presenting cells. Considering the absence of an effective treatment to prevent relapses of cutaneous melanoma, we applied this vaccination modality in an adjuvant setting. Methods and Results: We vaccinated 14 HLA-A2 melanoma patients with no evidence of disease but at high risk of relapse, with 4 antigenic peptides (MAGE-3.A2, NA17.A2, Tyrosinase.A2 and gp100.A2) emulsified in Montanide ISA51. Seven patients received 5 vaccinations, every 3 weeks, consisting of 4 injections of 900 μg of one peptide and 1 ml Montanide. Seven other patients received the same vaccines but with 300 μg of each peptide. Toxicity was limited to grade II, at the injection sites. Two thirds of the patients mounted a CTL response to peptide gp100.A2, and 50% to peptide NA17.A2. The lower doses of peptides were as immunogenic as the higher. Conclusions: These encouraging results indicate that this simple vaccination modality is not toxic and clearly immunogenic. We wish to formally assess the role of the immunological adjuvant Montanide in these CTL responses by vaccinating a third group of patients with the same 4 antigenic peptides without Montanide. We will also vaccinate with a mix of the 4 peptides and Montanide all injected at one site, as this will reduce the number of injections and could facilitate immunological helper effects of each peptide on the others. Finally, depending on the immunological results obtained with these two additional cohorts of patients, the best modality will be used in a larger study to evaluate clinical efficacy.

No significant financial relationships to disclose.

[The role of aortic morphology in the occurrence of hypertension in patients undergoing surgery for coarctation of the aorta before the age of 1 year]

OBJECTIVE

Hypertension on effort can be observed following surgical treatment of coarctation of the aorta even if the operation has been performed early and has been judged to be satisfactory. The pathophysiology of this hypertension has not been completely elucidated. The aim of our study was to look for a residual morphological anomaly of the aortic arch which might be responsible.

METHODS

This was a retrospective study of patients aged over 10 years who had undergone surgery for coarctation of the aorta before the age of 1 year, consecutively between 1979 and 1993, and free from re-coarctation clinically or with Doppler. All of them had a blood pressure effort test on a cycling machine, echocardiography and an MRI of the thoracic aorta.

RESULTS

61 patients were included. Their median age was 15 years, 59% were male, 15% were hypertensive at rest and 56% on effort. With univariate analysis, only the average blood pressure (p=0.03) and the resting pulse pressure (p=0.001) were associated with hypertension on effort. With multivariate analysis the only factors that correlated independently with maximum arterial pressure on effort were the height of the patient (p=0.02) and the pulse pressure (p<0.0001). The surgical technique and the age at intervention were not associated with hypertension on effort (p=0.96 and 0.69 respectively). The diameter of the horizontal aorta and the aorta at the site of repair, measured on MRI, added to the diameter of the descending aorta at the diaphragm were not lower in patients with hypertension on effort (p=0.77 and 0.38). There were proportionally more Roman type aortic arches than Gothic types in patients with hypertension on effort, but this difference was not significant (p=0.18).

CONCLUSION

In our study, the patients with hypertension on effort following correction of coarctation of the aorta did not display any residual obstruction at the level of the aortic cross on MRI. However, they had a resting pulse pressure that was significantly higher than the non hypertensive patients, reflecting an increase in the aortic wall rigidity.

[Quality of life of patients with total cavopulmonary anastomosis]

INTRODUCTION

Total cavo-pulmonary connection (TCPC) represents the current surgery standard for congenital univentricular heart disease (CUHD) patients. We studied the health related quality of life (HRQOL) expressed by TCPC operated patients.

PATIENTS AND METHODS

This transversal study is based on 24 children and 10 adult TCPC patients aged from 5 to 41 years old. The HRQOL evaluation relies on generic self report instruments such as the PedsQL 4.0 for the children and their parents, and the Duke Health profile for the adult patients. Additional questions were specifically designed for this study as well.

RESULTS AND DISCUSSION

The estimated HRQOL is 68.15 for the children and 68.71 for their parents. In these young cases, the global HRQOL or some specific score are altered when any comorbidity or scholar difficulties are present, or when TCPC was performed more than 10 years ago. The estimated HRQOL is 74.67 in adulthood. In these patients, the young age, the lifestyle, the onset of more than 2 early complications ans the necessity of anti-arrhythmia therapy decrease various HRQOL scores. The physical handicap is considered as the major limitation for children and adult patients. Thanks to adaptative and cognitive compensatory mechanisms, such as resilience, both groups express a satisfying HRQOL assessment.

CONCLUSION

Our study indicates that TCPC provides a good HRQOL in CUHD patients despite the complex management and follow-up of these diseases, the risk of complication onset and the physical handicap usually observed.