Saccharin and Sucralose Protect the Glomerular Microvasculature In Vitro against VEGF-Induced Permeability.

Diabetic kidney disease (DKD) has become a global health concern, with about 40% of people living with type 1 and type 2 diabetes mellitus developing DKD. Upregulation of vascular endothelial growth factor (VEGF) in the kidney is a significant pathology of DKD associated with increased glomerular vascular permeability. To date, however, current anti-VEGF therapies have demonstrated limited success in treating DKD. Recent studies have shown that artificial sweeteners exhibit anti-VEGF potential. The aim of this study was therefore to assess the effects of aspartame, saccharin, and sucralose on VEGF-induced leak using an in vitro model of the glomerular endothelium. Saccharin and sucralose but not aspartame protected against VEGF-induced permeability. Whilst the sweeteners had no effect on traditional VEGF signalling, GC-MS analysis demonstrated that the sweetener sucralose was not able to enter the glomerular endothelial cell to exert the protective effect. Chemical and molecular inhibition studies demonstrated that sweetener-mediated protection of the glomerular endothelium against VEGF is dependent on the sweet taste receptor, T1R3. These studies demonstrate the potential for sweeteners to exert a protective effect against VEGF-induced increased permeability to maintain a healthy endothelium and protect against vascular leak in the glomerulus in settings of DKD.

Mucociliary clearance in patients with continuous ambulatory peritoneal dialysis / Aclaramiento mucociliar en pacientes con diálisis peritoneal ambulatoria continua

INTRODUCTION: Mucociliary clearance (MC) is a critical defense mechanism for the protection of the entire respiratory system. Nasal colonization of some pathogens and chronical nasal infections are important risk factors for peritonitis. Any disturbance in the MC causes stasis of secretions and secondary infections. OBJECTIVE: The aim of the study was to evaluate the patients with chronic kidney disease (CKD) receiving continuous ambulatory peritoneal dialysis (CAPD) in terms of nasal MC. More specifically, the goal is to investigate the possible correlation between the nasal MC and peritonitis. METHODS: Forty CAPD patients and 39 healthy volunteers were involved in the study. The nasal MC was evaluated with the saccharin test, in which a 1 mm diameter saccharin particle was carefully placed on the antero-medial surface of inferior nasal concha. The time taken by the subjects from the placement of particle to the perception of the sweet taste was taken as mucociliary clearance time (MCT). The groups were compared in terms of MCT. The patient group was evaluated in terms of a peritonitis history, and the correlations with MC were analyzed. RESULTS: Patient group with CKD consisted of 16 females and 24 males with a mean age of 32.4 years; healthy individuals in the control group consisted of 17 women and 22 men with a mean age of 33.3 years. There was not a significant difference in terms of mean MC time in patients with CKD when compared with the individuals in the control group. The comparison between the mean MCT in the patients who had a history of peritonitis and patients without peritonitis was statistically significant (p < 0.05). CONCLUSIONS: Unique for being conducted with patients in continuous ambulatory peritoneal dialysis, the current study shows that although the MC of CKD patients and healthy individuals is similar, patients with low rates of MC appear to present an increased incidence of peritoneal infection. Considering the small sample investigated, an invitation to future confirmatory studies would be appropriate

INTRODUCCIÓN: El aclaramiento mucociliar (AM) es un mecanismo de defensa fundamental para la protección del sistema respiratorio. La colonización nasal de algunos patógenos y las infecciones nasales crónicas son factores de riesgo importantes de peritonitis. Cualquier alteración en el AM provoca estasis de secreciones e infecciones secundarias. OBJETIVO: El objetivo de este estudio fue evaluar el AM nasal de los pacientes con nefropatía crónica (NC) que recibían diálisis peritoneal ambulatoria continua (DPAC). Más concretamente, el objetivo fue estudiar la posible relación entre el AM nasal y la peritonitis. MÉTODOS: Cuarenta pacientes en DPAC y 39 voluntarios sanos participaron en el estudio. El AM nasal se evaluó con la prueba de sacarina, en la que se colocó cuidadosamente una partícula de sacarina, de 1 mm de diámetro, en la superficie anteromedial del cornete nasal inferior. El tiempo transcurrido desde el momento en que se colocó la partícula hasta que los pacientes percibieron el sabor dulce se consideró el tiempo de aclaramiento mucociliar (TAM), parámetro que se empleó para hacer la comparación entre los grupos. Se evaluaron los antecedentes de peritonitis en el grupo de pacientes y se analizaron las correlaciones con el AM. RESULTADOS: El grupo de pacientes con NC constó de 16 mujeres y 24 hombres con una media de edad de 32,4 años. Los pacientes sanos en el grupo control fueron 17 mujeres y 22 hombres con una media de edad de 33,3 años. No se observó una diferencia significativa en el tiempo medio de AM en pacientes con NC respecto a los pacientes del grupo control. La comparación entre el TAM medio en los pacientes con antecedentes de peritonitis y en pacientes sin peritonitis fue estadísticamente significativa (p < 0,05). CONCLUSIONES: Único por llevarse a cabo en pacientes con diálisis peritoneal ambulatoria continua, el estudio actual muestra que, aunque el AM de pacientes con NC y pacientes sanos es similar, los pacientes con tasas bajas de AM parecen presentar un aumento de la incidencia de infección peritoneal. Teniendo en cuenta la pequeña muestra estudiada, consideramos conveniente realizar nuevos estudios de confirmación

Mucociliary clearance in patients with continuous ambulatory peritoneal dialysis.

INTRODUCTION: Mucociliary clearance (MC) is a critical defense mechanism for the protection of the entire respiratory system. Nasal colonization of some pathogens and chronical nasal infections are important risk factors for peritonitis. Any disturbance in the MC causes stasis of secretions and secondary infections. OBJECTIVE: The aim of the study was to evaluate the patients with chronic kidney disease (CKD) receiving continuous ambulatory peritoneal dialysis (CAPD) in terms of nasal MC. More specifically, the goal is to investigate the possible correlation between the nasal MC and peritonitis. METHODS: Forty CAPD patients and 39 healthy volunteers were involved in the study. The nasal MC was evaluated with the saccharin test, in which a 1mm diameter saccharin particle was carefully placed on the antero-medial surface of inferior nasal concha. The time taken by the subjects from the placement of particle to the perception of the sweet taste was taken as mucociliary clearance time (MCT). The groups were compared in terms of MCT. The patient group was evaluated in terms of a peritonitis history, and the correlations with MC were analyzed. RESULTS: Patient group with CKD consisted of 16 females and 24 males with a mean age of 32.4 years; healthy individuals in the control group consisted of 17 women and 22 men with a mean age of 33.3 years. There was not a significant difference in terms of mean MC time in patients with CKD when compared with the individuals in the control group. The comparison between the mean MCT in the patients who had a history of peritonitis and patients without peritonitis was statistically significant (p<0.05). CONCLUSIONS: Unique for being conducted with patients in continuous ambulatory peritoneal dialysis, the current study shows that although the MC of CKD patients and healthy individuals is similar, patients with low rates of MC appear to present an increased incidence of peritoneal infection. Considering the small sample investigated, an invitation to future confirmatory studies would be appropriate.

Nasal mucociliary transportability of male and female smokers / Transportabilidade mucociliar nasal de homens e mulheres tabagistas

Abstract Introduction: Female smoker's present increased susceptibility to several diseases when compared to the opposite gender. However, there are no studies showing differences in nasal mucociliary transport behavior between male and female smokers. Objective: To compare the nasal mucociliary transportability in male and female smokers and non-smokers, taking into consideration age, anthropometric data, smoking load and pulmonary function. Methods: The analysis included 139 individuals (33 men and 37 women smokers and 32 men and 37 women non-smokers). All participants answered an initial interview to obtain personal data and smoking load. Anthropometric data and carbon monoxide in the exhaled air were assessed. Individuals also performed pulmonary function test and Saccharin Transit Time test. To compare saccharin transit time values between men and women, smokers and non-smokers, stratification of all independent variables was performed (sociodemographic, smoking and respiratory variables) into two categories: below and above the median values. Results: There was no difference between men and women, smokers and non-smokers, regarding nasal mucociliary transportability. Significant differences were only observed between non-smokers. Among those with less forced vital capacity values (<97.37% of predicted), women presented mucociliary transport faster than men. Moreover, it was observed influence of BMI and COex (women smokers), FCV and FEV1 (men non-smokers) and FEF25-75% (women non-smokers) on saccharin transit time values. Conclusion: Based on the findings of this study, nasal mucociliary transport in male and female adult smokers, apparently healthy, are similar.

Resumo Introdução: Mulheres tabagistas apresentam maior susceptibilidade à diversas doenças quando comparadas ao sexo masculino. No entanto, não há estudos mostrando diferenças no comportamento do transporte mucociliar nasal entre tabagistas do sexo masculino e feminino. Objetivo: Comparar a transportabilidade mucociliar nasal em homens e mulheres fumantes e não fumantes, levando em consideração idade, dados antropométricos, carga tabágica e função pulmonar. Método: A análise incluiu 139 indivíduos (33 homens e 37 mulheres fumantes e 32 homens e 37 mulheres não fumantes). Todos os participantes responderam a uma entrevista inicial para a obtenção de dados pessoais e a carga tabágica. Dados antropométricos e monóxido de carbono no ar expirado foram avaliados. Os indivíduos também fizeram teste de função pulmonar e o teste de trânsito de sacarina. Para comparar os valores do teste de trânsito de sacarina entre homens e mulheres, fumantes e não fumantes, foi feita a estratificação de todas as variáveis independentes (variáveis sociodemográficas, tabágicas e respiratórias) em duas categorias: abaixo e acima dos valores médios. Resultados: Não houve diferenças entre homens e mulheres, fumantes e não fumantes, em relação à transportabilidade mucociliar nasal. Diferenças significativas foram observadas apenas entre não fumantes. Entre os que apresentaram valores menores de capacidade vital forçada (< 97,37% do previsto), as mulheres apresentaram transporte mucociliar mais rápido do que os homens. Além disso, observou-se influência do IMC e COex (mulheres fumantes), CVF e VEF1 (homens não fumantes) e FEF25%-75% (mulheres não fumantes) sobre os valores do teste de trânsito de sacarina. Conclusão: Com base nos achados deste estudo, o transporte mucociliar nasal em tabagistas masculinos e femininos adultos, aparentemente saudáveis, são semelhantes.

Evaluation of nasal mucociliary clearance using saccharin test in smokers: A prospective study.

BACKGROUND AND AIM: Nasal mucociliary clearance time (NMCT) can be measured with the saccharine clearance test which is an inexpensive and easy method. The aim of the present study was to compare and evaluate NMCT using the saccharine clearance test in smokers and non-smokers. MATERIALS AND METHODS: Eighty-five patients whose ages ranged from 18 to 65 years were included in the study. Fifty of the patients were smokers (Group 1) while 35 were healthy, non-smoking volunteers (Group 2). Saccharin clearance test was used to evaluate NMCT in both groups. The results obtained were compared and the statistical analyses were performed using the Statistical Package for Social Sciences (SPSS). RESULTS: NMCT was statistically significantly higher in Group 1 as compared to Group 2 (P < .001, Mann-Whitney U test). However, in cumulative smoking duration (pack-year), Fagerström test values and gender categories, there was no statistically significant difference in the average NMCT values of the two groups (P = .943 vs P = .812 respectively), P = .45). CONCLUSION: Mucociliary activity, the primary defence mechanism of the respiratory epithelium, is significantly depressed in smokers. Our findings showed that the said depression is not associated with the number of cigarettes smoked, duration of smoking or nicotine dependence.

Nasal mucociliary transportability of male and female smokers.

INTRODUCTION: Female smoker's present increased susceptibility to several diseases when compared to the opposite gender. However, there are no studies showing differences in nasal mucociliary transport behavior between male and female smokers. OBJECTIVE: To compare the nasal mucociliary transportability in male and female smokers and non-smokers, taking into consideration age, anthropometric data, smoking load and pulmonary function. METHODS: The analysis included 139 individuals (33 men and 37 women smokers and 32 men and 37 women non-smokers). All participants answered an initial interview to obtain personal data and smoking load. Anthropometric data and carbon monoxide in the exhaled air were assessed. Individuals also performed pulmonary function test and Saccharin Transit Time test. To compare saccharin transit time values between men and women, smokers and non-smokers, stratification of all independent variables was performed (sociodemographic, smoking and respiratory variables) into two categories: below and above the median values. RESULTS: There was no difference between men and women, smokers and non-smokers, regarding nasal mucociliary transportability. Significant differences were only observed between non-smokers. Among those with less forced vital capacity values (<97.37% of predicted), women presented mucociliary transport faster than men. Moreover, it was observed influence of BMI and COex (women smokers), FCV and FEV1 (men non-smokers) and FEF25-75% (women non-smokers) on saccharin transit time values. CONCLUSION: Based on the findings of this study, nasal mucociliary transport in male and female adult smokers, apparently healthy, are similar.

Biological fate of low-calorie sweeteners.

With continued efforts to find solutions to rising rates of obesity and diabetes, there is increased interest in the potential health benefits of the use of low- and no-calorie sweeteners (LNCSs). Concerns about safety often deter the use of LNCSs as a tool in helping control caloric intake, even though the safety of LNCS use has been affirmed by regulatory agencies worldwide. In many cases, an understanding of the biological fate of the different LNSCs can help health professionals to address safety concerns. The objectives of this review are to compare the similarities and differences in the chemistry, regulatory status, and biological fate (including absorption, distribution, metabolism, and excretion) of the commonly used LNCSs: acesulfame potassium, aspartame, saccharin, stevia leaf extract (steviol glycoside), and sucralose. Understanding the biological fate of the different LNCSs is helpful in evaluating whether reports of biological effects in animal studies or in humans are indicative of possible safety concerns. Illustrations of the usefulness of this information to address questions about LNCSs include discussion of systemic exposure to LNCSs, the use of sweetener combinations, and the potential for effects of LNCSs on the gut microflora.

Occurrence of artificial sweeteners in human liver and paired blood and urine samples from adults in Tianjin, China and their implications for human exposure.

In this study, acesulfame (ACE), saccharin (SAC) and cyclamate (CYC) were found in all paired urine and blood samples collected from healthy adults, with mean values of 4070, 918 and 628 ng mL(-1), respectively, in urine and 9.03, 20.4 and 0.72 ng mL(-1), respectively, in blood. SAC (mean: 84.4 ng g(-1)) and CYC (4.29 ng g(-1)) were detectable in all liver samples collected from liver cancer patients, while ACE was less frequently detected. Aspartame (ASP) was not found in any analyzed human sample, which can be explained by the fact that this chemical metabolized rapidly in the human body. Among all adults, significantly positive correlations between SAC and CYC levels were observed (p < 0.001), regardless of human matrices. Nevertheless, no significant correlations between concentrations of SAC (or CYC) and ACE were found in any of the human matrices. Our results suggest that human exposure to SAC and CYC is related, whereas ACE originates from a discrete source. Females (or young adults) were exposed to higher levels of SAC and CYC than males (or elderly). The mean renal clearance of SAC was 730 mL per day per kg in adults, which was significantly (p < 0.001) lower than those for CYC (10 800 mL per day per kg) and ACE (10 300 mL per day per kg). The average total daily intake of SAC and ACE was 9.27 and 33.8 µg per kg bw per day, respectively.

Effects of cigarette smoking intensity on the mucociliary clearance of active smokers.

BACKGROUND: Smoking impairs mucociliary clearance and increases respiratory infection frequency and severity in subjects with and without smoking-related chronic lung diseases. OBJECTIVE: This study evaluated the effects of smoking intensity on mucociliary clearance in active smokers. METHODS: Seventy-five active smokers were grouped into light (1-10 cigarettes/day; n = 14), moderate (11-20 cigarettes/day; n = 34) and heavy smokers (≥21 cigarettes/day; n = 27) before starting a smoking cessation programme. Smoking behaviour, nicotine dependence, pulmonary function, carbon monoxide in exhaled air (exCO), carboxyhaemoglobin (COHb) and mucociliary clearance measured by the saccharin transit time (STT) test were all evaluated. An age-matched non-smoker group (n = 24) was assessed using the same tests. RESULTS: Moderate (49 ± 7 years) and heavy smokers (46 ± 8 years) had higher STT (p = 0.0001), exCO (p < 0.0001) and COHb (p < 0.0001) levels compared with light smokers (51 ± 15 years) and non-smokers (50 ± 11 years). A positive correlation was observed between STT and exCO (r = 0.4; p < 0.0001), STT and cigarettes/day (r = 0.3, p = 0.02) and exCO and cigarettes/day (r = 0.3, p < 0.01). CONCLUSION: Smoking impairs mucociliary clearance and is associated with cigarette smoking intensity.

Bioavailability of indomethacin-saccharin cocrystals.

OBJECTIVES: Pharmaceutical cocrystals are new solid forms with physicochemical properties that appear promising for drug product development. However, the in-vivo bioavailability of cocrystals has rarely been addressed. The cocrystal of indomethacin (IND), a Biopharmaceutical Classification System class II drug, with saccharin (SAC) has been shown to have higher solubility than IND at all pH. In this study, we aimed to evaluate the in-vitro dissolution and in-vivo bioavailability of IND-SAC cocrystals in comparison with IND in a physical mixture and the marketed product Indomee. METHODS: Scale-up of the cocrystals was undertaken using cooling batch crystallisation without seeding. The chemical and physical purity of the up-scaled material was verified using high-performance liquid chromatography, differential scanning calorimetry and powder X-ray diffraction. The IND-SAC cocrystals and IND plus SAC were mixed with lactose and the formulations were placed into gelatin capsules. In-vitro dissolution studies were then performed using the rotating basket dissolution method. The intrinsic dissolution rate of IND and IND-SAC cocrystals was also determined. Finally, a bioavailability study for the formulations was conducted in beagle dogs. The plasma samples were analysed using high-performance liquid chromatography and the pharmacokinetic data were analysed using standard methodologies. KEY FINDINGS: The bulk cocrystals (i.e. scaled-up material) were chemically and physically pure. The in-vitro dissolution rate of the cocrystals was higher than that of IND and similar to that of Indomee at pH 7.4 and pH 1.2. The in-vivo bioavailability of the IND-SAC cocrystals in dogs was significantly higher (ANOVA, P<0.05) than that of IND but not significantly different from Indomee (ANOVA, P>0.05). CONCLUSIONS: The study indicates that the improved aqueous solubility of the cocrystals leads to improved bioavailability of IND. Thus, the cocrystals are a viable alternative solid form that can improve the dissolution rate and bioavailability of poorly soluble drugs.

Overshadowing and potentiation of illness-based context conditioning

En cinco experimentos, se investigó el condicionamientocompuesto sabor-contexto empleando ratas como sujetos. Los animalesfueron expuestos a un contexto novedoso en el que tenían acceso a unasolución de ácido cítrico ó de sacarina antes de ser inyectados con LiCl. Acontinuación medimos la aversión condicionada al contexto empleando unprocedimiento de bloqueo. Cuando el sabor que acompañaba al contextodurante el condicionamiento era relativamente aversivo (ácido cítrico)observamos un nivel relativamente bajo de condicionamiento contextual; deacuerdo con nuestra interpretación, el sabor ácido ensombreció al contexto.Por el contrario, cuando el sabor era agradable (solución de sacarina) seobservó una potenciación del condicionamiento contextual. Nuestradiscusión de los resultados toma en consideración las propiedadesmotivacionales del sabor que acompaña a contexto en el momento delcondicionamiento(AU)

In five experiments using rats, we investigated compound context-flavorconditioning. The subjects were allowed to spend time in the target context,where they had access to a flavored solution (either citric acid or saccharine)before receiving an injection of LiCl. Context aversion was then assessed byusing a blocking procedure. When the flavor accompanying the context wasa non-palatable one, citric acid, impaired learning about the context wasobserved, an instance of overshadowing. However, when we presentedsaccharine in the novel environment enhanced learning about the contextwas found, an instance of context potentiation. The role of the motivationalproperties of the flavor that accompanies the target context duringconditioning is discussed(AU)

Physiological and subjective responses to low relative humidity in young and elderly men.

In order to compare the physiological and the subjective responses to low relative humidity of elderly and young men, we measured saccharin clearance time (SCT), frequency of blinking, hydration state of the skin, transepidermal water loss (TEWL), sebum level recovery and skin temperatures as physiological responses. We asked subjects to evaluate thermal, dryness and comfort sensations as subjective responses using a rating scale. Eight non-smoking healthy male students (21.7+/-0.8 yr) and eight non-smoking healthy elderly men (71.1+/-4.1 yr) were selected. The pre-room conditions were maintained at an air temperature (Ta) of 25 degrees C and a relative humidity (RH) of 50%. The test-room conditions were adjusted to provide 25 degrees C Ta and RH levels of 10%, 30% and 50%. RH had no effect on the activity of the sebaceous gland or change of mean skin temperature. SCT of the elderly group under 10% RH was significantly longer than that of the young group. In particular, considering the SCT change, the nasal mucous membrane seems to be affected more in the elderly than in the young in low RH. Under 30% RH, the eyes and skin become dry, and under 10% RH the nasal mucous membrane becomes dry as well as the eyes and skin. These findings suggested that to avoid dryness of the eyes and skin, it is necessary to maintain greater than 30% RH, and to avoid dryness of the nasal mucous membrane, it is necessary to maintain greater than 10% RH. On the thermal sensation of the legs, at the lower humidity level, the elderly group felt cooler than the young group. On the dry sensation of the eyes and throat, the young group felt drier than the elderly group at the lower humidity levels. From the above results, the elderly group had difficulty in feeling dryness in the nasal mucous membrane despite being easily affected by low humidity. On the other hand, the young group felt the change of humidity sensitively despite not being severely affected by low humidity. Ocular mucosa and physiology of skin by dryness showed no difference by age. In the effect of longer exposure (180 min.) to low RH, only TEWL showed a slight decrease after 120 minutes in 30% RH, and all the measured results showed no noticeable differences compared with the result at 120 minutes.

Scanning electron microscopy of ciliae and saccharine test for ciliary function in septal deviations.

OBJECTIVE: To investigate the difference in mucociliary clearance and surface mucosal structure of the nasal septum and lateral nasal wall in patients with and without septal deviation. METHOD: The saccharine-dye test was used to measure the mucociliary clearance time in both nasal cavities of 20 patients with nasal septal deviation (study group) and was compared with that of 30 patients without septal deviation (control group). Bilateral septal and lateral nasal wall mucosal biopsies were taken from the study group during septoplasty, and unilateral biopsies were taken from 10 of the control group. These biopsies were studied under the scanning electron microscope. RESULTS: In the study group, mucociliary clearance on the side opposite the septal deviation was significantly slower than on the other side. Mucociliary clearance on both sides of the deviated septum of the study group was significantly slower than clearance in the control group. There was no statistically significant difference in the distribution of mucosal cilia of the cavities on either side of the deviated septum in the study group, nor between the distribution in the study group and controls. CONCLUSION: Patients with septal deviation display no change in mucosal surface anatomy but have decreased mucociliary activity on both sides of the deviation, the least activity being on the side opposite the deviation.

Mucociliary clearance is impaired in acutely ill patients.

OBJECTIVE: This study aimed to investigate nasal mucociliary clearance in acutely ill patients who were clinically stable and had no airway manipulation. DESIGN: Prospective clinical study. SETTING: Medical ICU. PATIENTS AND PARTICIPANTS: Sixteen medical patients admitted to the ICU and 16 healthy subjects were studied. Patients who were receiving airway manipulation, including tracheal suctioning, nasogastric or enteral tubes, noninvasive and invasive mechanical ventilation, were excluded. INTERVENTIONS: Mucociliary clearance was evaluated by saccharine transit time (STT) measurements at ICU admission (admission) and 90 days after hospital discharge (recovery). Healthy subjects were also subjected to two measurements 90 days apart. MEASUREMENTS AND RESULTS: The STT of patients was 26.4 +/- 11.3 min and 17.9 +/- 8.6 min at admission and recovery (p = 0.002) [mean +/- SD] but did not change along the 90-day interval in healthy subjects (17.2 +/- 10.2 min and 16.7 +/- 10.3 min), respectively. Smokers (patients and healthy subjects) presented prolonged STT when compared to nonsmokers (p = 0.026). STT at admission correlated positively with heart rate (r = 0.560; p = 0.024) and hospital stay (r = 0.634; p = 0.008). CONCLUSION: Mucociliary clearance is impaired in stable acutely ill patients with no airway manipulation and correlates with simple markers of underlying disease severity. Mucociliary dysfunction may help to explain the increased susceptibility of hospital-acquired respiratory infection in critically ill patients.

Nasal mucociliary clearance in coal mine workers.

OBJECTIVE: The purpose of this study was to analyze the effect of coal dust particles on nasal mucociliary function in coal mine workers. METHOD: Using the saccharin method, nasal mucociliary clearance was determined for 77 subjects, of which 39 who worked in a coal mine were actively exposed to coal dust whereas 38 were unexposed control subjects. The measurements were performed in the coal mine, at the level of 170 m below sea level. RESULTS: The average saccharin nasal transit time in coal mine workers, 12.61 (SD: 4.30) minutes, is longer than that of the control subjects, 10.97 (SD: 3.22). CONCLUSION: Although the findings of this study demonstrate that the coal particles affect the nasal mucociliary clearance, the difference in saccharin nasal transit time between the two groups (exposed vs unexposed) is not statistically significant (P = 0.063).

The effect of hypertonicity on nasal mucociliary clearance.

The effect of the tonicity of saline nasal douching solutions on mucociliary clearance was studied in order to ascertain whether hypertonicity conferred any advantage. Thirty-eight normal subjects were included in a randomised double-blind crossover trial. Saline douching solutions of 0.9%, 3% and 5% tonicity were used and mucociliary clearance was measured by the saccharin clearance time (SCT). The resultant SCT after administration of 5% saline was significantly reduced compared to both 0.9% (P = 0.005) and 3% saline (P = 0.04). There was no difference between 0.9% and 3% saline administration. Thus hypertonic saline solutions improve mucociliary clearance, although this was only observed with solutions of 5% tonicity. The effect is probably brought about by changes in mucus rheology.