71 Pharmacokinetics of nasal administered tobramycin in patients with cystic fibrosis

Recent studies showed that the paranasal sinuses can constitute a niche for bacteria. To date no effective treatment for these bacteria is available. Off label administration of nasal antibiotics may be an option. However, first safety of this treatment has to be established. Objectives: With this pilot study in two patients the pharmacokinetic parameters of nasal administered tobramycin were investigated. Methods: In two hospitalised CF-patients, treated with intravenous tobramycin, after a wash-out period, 320 mg of tobramycin, dissolved in 200 ml isotonic saline, was administered to the nose using nasal lavage. Eleven venous blood samples were collected and with a Liquid Chromatography Tandem Mass Spectometer (LCMSMS) method, serum tobramycin concentrations were determined. Tobramycin pharmacokinetic parameters were calculated using the MW\Pharm software package. Systemic absorption was calculated by dividing AUC after nasal administration by AUC after intravenous administration corrected for the administered dose. Results: In patient 1, a female of 32 years old, the maximum concentration (Cmax) of tobramycin was 0.027 mg/L. This Cmax was reached 30 minutes after the nasal lavage with tobramycin (tmax). In total 0.20% (0.62 mg) of the tobramycin was systemically absorbed. In patient 2, a male of 36 years old, the Cmax was 0.029 mg/L. The tmax was 45 minutes and in total 0.16% (0.51 mg) of tobramycin was absorbed. Conclusion: Nasal lavage with 320 mg tobramycin did not result in toxic serum levels. The results of two patients showed a fast absorption of tobramycin and a slow elimination. Approximately 0.20% of the tobramycin was absorbed by the sinonasal mucosa

The effect of nasal steroid aqueous spray on nasal complaint scores and cellular infiltrates in the nasal mucosa of patients with nonallergic, noninfectious perennial rhinitis

Topical corticosteroids are the therapy of choice for nonallergic, noninfectious perennial rhinitis (NANIPER). However, the efficacy of steroid therapy in NANIPER is controversial, as is its mode of action. To our surprise, of 300 patients initially diagnosed as having NANIPER, only 65 reached threshold nasal symptom scores. Patients were randomized into four different treatment regimens: placebo administered twice daily (BD) for 8 weeks, fluticasone propionate aqueous nasal spray (FPANS) (200 microg) once daily (OD) and placebo OD for 8 weeks, FPANS (200 microg) OD and placebo OD for 4 weeks followed by FPANS (200 microg) BD for 4 weeks, and FPANS (200 microg) BD for 8 weeks. A small decrease in nasal symptoms was found, which only reached significance for sneezing in the FPANS 200 microg BD group. A significant dose-dependent decrease in immunocompetent cells was found in nasal biopsy specimens obtained before, after 4 weeks, and after 8 weeks of treatment. We conclude that FPANS did not significantly reduce nasal symptoms in this group of selected NANIPER patients, even though a significant effect on cells in the nasal mucosa was see

Intranasal cold dry air is superior to histamine challenge in determining the presence and degree of nasal hyperreactivity in nonallergic noninfectious perennial rhinitis

The objective of the study was to compare cold dry air (CDA) and histamine in differentiating patients with nonallergic noninfectious perennial rhinitis (NANIPER) from control subjects. Nasal reactivity (nasal patency, mucus production, and sneezing) in 16 symptomatic nonsmoking patients with NANIPER and seven nonsmoking control subjects was measured with standardized CDA and histamine provocation series in a randomized crossover study. Intranasal CDA resulted in increased mucus production and nasal blockage in a dose-dependent manner in patients with NANIPER but not in control subjects. Sneezing did not occur. The reproducibility of CDA for patency and mucus production was good. Sen

Mast cells, eosinophils and IgE-positive cells in the nasal mucose of patients with vasomotor rhinitis - An immunohistochemical study

Vasomotor rhinitis (VMR) is a disorder of unknown pathogenesis. Forty patients with VMR were carefully selected on the basis of inclusion and exclusion criteria proposed by Mygind and Weeke. Nasal biopsy specimens were taken in the patient group as well as in a group of ten controls. Brush cytology was also taken in the VMR group. Inflammatory cells were identified and counted in the nasal mucosa, with the use of immunohistochemical techniques and a panel of monoclonal antibodies. Eosinophils were studied with the use of BMK13, EG2, and Giemsa. Mast cells were studied with anti-chymase (B7), anti-tryptase (G3) and toluidine blue. Sections were stained with IgE as well. There was no significant difference in the number of eosinophils, mast cells and IgE-positive cells between the two groups. Additionally, in contrast with other reports, in sections that were double-stained with anti-chymase and anti-tryptase, single chymase-positive cells were found

Testing for heterotopia formation in rats after developmental exposure to selected in vitro inhibitors of thyroperoxidase

© 2021 The Authors. The thyroperoxidase (TPO) enzyme is expressed by the thyroid follicular cells and is required for thyroid hormone synthesis. In turn, thyroid hormones are essential for brain development, thus inhibition of TPO in early life can have life-long consequences for brain function. If environmental chemicals with the capacity to inhibit TPO in vitro can also alter brain development in vivo through thyroid hormone dependent mechanisms, however, remains unknown. In this study we show that the in vitro TPO inhibiting pesticide amitrole alters neuronal migration and induces periventricular heterotopia; a thyroid hormone dependent brain malformation. Perinatal exposure to amitrole reduced pup serum thyroxine (T4) concentrations to less than 50% of control animals and this insufficiency led to heterotopia formation in the 16-day old pup's brain. Two other in vitro TPO inhibitors, 2-mercaptobenzimidazole and cyanamide, caused reproductive toxicity and had only minor sporadic effects on the thyroid hormone system; consequently, they did not cause heterotopia. This is the first demonstration of an environmental chemical causing heterotopia, a brain malformation until now only reported for rodent studies with the anti-thyroid drugs propylthiouracil and methimazole. Our results highlight that certain TPO-inhibiting environmental chemicals can alter brain development through thyroid hormone dependent mechanisms. Improved understanding of the effects on the brain as well as the conditions under which chemicals can perturb brain development will be key to protect human health.ATHENA project (Assays for the identification of Thyroid Hormone axis-disrupting chemicals: Elaborating Novel assessment strategies); (Kortenkamp et al., 2020) funded by the EU Horizon 2020 programme, grant number 825161

Beta-carotene affects gene expression in lungs of male and female Bcmo1−/− mice in opposite directions

Molecular mechanisms triggered by high dietary beta-carotene (BC) intake in lung are largely unknown. We performed microarray gene expression analysis on lung tissue of BC supplemented beta-carotene 15,15′-monooxygenase 1 knockout (Bcmo1−/−) mice, which are—like humans—able to accumulate BC. Our main observation was that the genes were regulated in an opposite direction in male and female Bcmo1−/− mice by BC. The steroid biosynthetic pathway was overrepresented in BC-supplemented male Bcmo1−/− mice. Testosterone levels were higher after BC supplementation only in Bcmo1−/− mice, which had, unlike wild-type (Bcmo1+/+) mice, large variations. We hypothesize that BC possibly affects hormone synthesis or metabolism. Since sex hormones influence lung cancer risk, these data might contribute to an explanation for the previously found increased lung cancer risk after BC supplementation (ATBC and CARET studies). Moreover, effects of BC may depend on the presence of frequent human BCMO1 polymorphisms, since these effects were not found in wild-type mice

Excitability of the Motor Cortex Ipsilateral to the Moving Body Side Depends on Spatio-Temporal Task Complexity and Hemispheric Specialization

Unilateral movements are mainly controlled by the contralateral hemisphere, even though the primary motor cortex ipsilateral (M1ipsi) to the moving body side can undergo task-related changes of activity as well. Here we used transcranial magnetic stimulation (TMS) to investigate whether representations of the wrist flexor (FCR) and extensor (ECR) in M1ipsi would be modulated when unilateral rhythmical wrist movements were executed in isolation or in the context of a simple or difficult hand-foot coordination pattern, and whether this modulation would differ for the left versus right hemisphere. We found that M1ipsi facilitation of the resting ECR and FCR mirrored the activation of the moving wrist such that facilitation was higher when the homologous muscle was activated during the cyclical movement. We showed that this ipsilateral facilitation increased significantly when the wrist movements were performed in the context of demanding hand-foot coordination tasks whereas foot movements alone influenced the hand representation of M1ipsi only slightly. Our data revealed a clear hemispheric asymmetry such that MEP responses were significantly larger when elicited in the left M1ipsi than in the right. In experiment 2, we tested whether the modulations of M1ipsi facilitation, caused by performing different coordination tasks with the left versus right body sides, could be explained by changes in short intracortical inhibition (SICI). We found that SICI was increasingly reduced for a complex coordination pattern as compared to rest, but only in the right M1ipsi. We argue that our results might reflect the stronger involvement of the left versus right hemisphere in performing demanding motor tasks