Transmission electron microscopy in the diagnosis of primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease with extensive genetic heterogeneity. Dyskinetic or completely absent motility of cilia predisposes to recurrent pulmonary and upper respiratory tract infections resulting in bronchiectasis. Also infections of the middle ear are common due to lack of ciliary movement in the Eustachian tube. Men have reduced fertility due to spermatozoa with absent motility or abnormalities in the ductuli efferentes. Female subfertility and tendency to ectopic pregnancy has also been suggested. Headache, a common complaint in PCD patients, has been associated with absence of cilia in the brain ventricles, leading to decreased circulation of the cerebrospinal fluid. Finally, half of the patients with PCD has situs inversus, probably due to the absence of ciliary motility in Hensen's node in the embryo, which is responsible for the unidirectional flow of fluid on the back of the embryo, which determines sidedness. PCD, which is an inborn disease, should be distinguished from secondary ciliary dyskinesia (SCD) which is an acquired disease. Transmission electron microscopy is the most commonly used method for diagnosis of PCD, even though alternative methods, such as determination of ciliary motility and measurement of exhaled nitric oxide (NO) may be considered. The best method to distinguish PCD from SCD is the determination of the number of inner and outer dynein arms, which can be carried out reliably on a limited number of ciliary cross-sections. There is also a significant difference in the ciliary orientation (determined by the direction of a line drawn through the central microtubule pair) between PCD and SCD, but there is some overlap in the values, making this parameter less suitable to distinguish PCD from SCD.

Attachment of columnar airway epithelial cells in asthma.

Shedding of airway epithelial cells is a common finding in asthma. In this study, the attachment of the airway epithelial cells to the basal lamina (BL) was investigated by transmission electron microscopy (TEM) of biopsies from patients with atopic asthma and healthy controls. The following parameters were quantitatively determined: the height of the epithelium and of the columnar cells, the number of basal cells per 100 microm of basal lamina, the contact surfaces of basal cells or columnar cells with the basal lamina, and between basal cells and columnar cells. In order to compare the quantitative method with previous literature data, measurements were also carried out on rat airway epithelium. Compared to the rat, the columnar cell height in the human is increased, basal cells are smaller, and there is a larger contact area between basal cells and basal lamina, as well as between basal and columnar cells. The contact area between columnar cells and basal lamina is hence less in the human airway. The contact area between columnar cells and basal lamina in asthmatics is significantly less than in healthy controls, due to larger intercellular spaces. It is concluded that attachment of columnar cells to the basal lamina occurs mainly indirectly, via desmosomal attachment to basal cells, and that direct attachment of columnar cells to the basal lamina is weakened in asthmatics.

A patient with type 2 Gaucher's disease with respiratory disease.

A 5-month-old boy had respiratory problems and gastroesophageal reflux. Electron microscopy of a tracheal biopsy specimen showed accumulation of lamellar bodies in the columnar cells indicative of lysosomal storage disease. Subsequently, the child had neurologic symptoms and hepatosplenomegaly, and the diagnosis of Gaucher's disease type 2 was made.