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B A Afzelius

Publications and source records attributed to B A Afzelius.

At least 55 records · Page 3Linked to original sources
PubMed1988

Acrosome formation during spermiogenesis in Notonecta glauca L. (Heteroptera).

The giant spermatozoon of Notonecta glauca has a 1 mm long acrosome. It has the shape of a stiff needle with round cross section and contains several different components. Morphogenesis of this simple form proceeds by very complex changes of both the internal structure and the outer shape. Surrounded by a great number of individual dictyosomes the acrosome is attached to the anterior nuclear pole where it grows to a sphere measuring about 20 microns in diameter. In its interior differentiations consisting of several components become visible which develop independently and may be characterized as basal and lateral complexes. At the end of the growing phase these two complexes come in contact with each other. After the dictyosomes have detached from the acrosome, the cell membrane surrounds the acrosome very closely so that cytoplasmic structures temporarily disappear completely from the narrow space in between. The tip of the acrosome grows out of the sphere as a slender lateral process which becomes increasingly spiralized. It shows a deep lateral groove, its contents consist of components of the basal complex. Parts of the lateral complex form a baso-lateral protuberance. Between these two structures a narrow channel extends from the subacrosomal space to the base of the lateral process. During elongation the acrosome attains spindle shape, the lateral process gradually becoming its anterior part. The distance between acrosome and cell membrane broadens again and cytoplasmic structures reappear among them about 1000 microtubules which are not surrounded by a sleeve membrane. In the posterior part cell membrane and acrosomal membrane are connected by two lines of weld spots where acrosomal membrane is eliminated as small vesicles. In the anterior part the groove becomes deeper. One leg of its initially U-shaped cross section becomes longer and is wrapped around the shorter one. The two legs subsequently fuse with the consequence that membrane and cytoplasmic components of the former groove become secondarily incorporated into the acrosome. The subacrosomal channel obliterates and the cross section of the acrosome showing acute angles in later stages finally gets round. Anterior and posterior part of the acrosome can be differentiated due to structural details even in the mature sperm.

Acrosome↗
PubMed1987

Interpretation of electron micrographs.

Courses in electron microscopical techniques should include training in the active reading of electron micrographs. The student should be made aware of the fact that every micrograph contains a wealth of information, evident and hidden, and that a careful inspection is required to retrieve the information. More time should normally be spent in scrutinizing the micrograph than in its manufacture. Active reading of the micrograph is aided by a curiosity in the functional significance of the various details of the picture; there has to be a dialogue between the mind and the eye concerning the structural elements and their significance. The investigator also has to be critical with respect to the possibility of technical flaws and should further be on guard against "seeing" such patterns that others may have seen and have described but which actually do not exist in the micrograph. Among examples given for an analysis in this paper are flaws in the metal shadowing technique and in ultrathin sections that have undergone deformation.

Animals↗
PubMed1986

Alignment of cilia in immotile-cilia syndrome.

Alignment of cilia in nasal epithelial cells from eight human subjects suffering from immotile-cilia syndrome was compared with that of cells from five control subjects. Individual cilia were assessed according to the orientation of their basal feet. The range of orientation of basal feet on a single cell varied from 26 degrees to 261 degrees and 54 degrees to 275 degrees in controls and patients respectively. Less than 10% of the cells from each group supported cilia that were aligned randomly. Alignment was worse in subjects with immotile-cilia syndrome but this could well have been due to secondary characteristics of the disease, such as common viral infection. Very accurate alignment of mucus-propelling cilia may be unnecessary. Measurements from control subjects and some invertebrates suggest that ranges of 140 degrees are common and do not seriously impair mucus propulsion.

Cilia↗
PubMed1985

The immotile-cilia syndrome: a microtubule-associated defect.

The immotile-cilia syndrome is a congenital disorder characterized by all the cilia in the body being either immotile or showing an abnormal and inefficient beating pattern. Most symptoms come from the ciliated airways (nose, paranasal sinuses, and bronchs) and from the middle ear. Two further symptoms are situs inversus and male sterility. Situs inversus occurs in 50% of the cases and this subgroup is termed the Kartagener's syndrome; it might be due to an inability of the embryonic cilia to shift the heart to the left side and situs laterality seems to be a random process in the immotile-cilia syndrome. Male sterility is caused by the spermatozoa being unable to swim progressively; the sperm tail has the same structure as a cilium. In a few cases only the sperm tail or only the cilia of the body are affected. Female patients have a decreased fertility; most are involuntarily childless. The immotile-cilia syndrome is a heterogeneous disorder in that one out of many different genes may be involved. The different subtypes can be distinguished by an electron microscopic examination which will show defects in either one of a number of the ciliary components.

Animals↗
PubMed1985

Abnormal length of cilia as a possible cause of defective mucociliary clearance.

A 12-year-old girl with obstructive lung disease was examined with respect to the ultrastructure of her nasal mucociliate epithelium. She had the characteristics of the immotile-cilia syndrome: chronic rhinitis, sinusitis, and bronchitis, a severely decreased mucociliary clearance of the lungs, and nasal polyps. The nasal cilia showed a normal cross-sectional appearance but were found to have twice the normal length: 12 micron rather than 6 micron. We conclude that the patient represents a new subgroup of the immotile-cilia syndrome and that her cilia are unable to perform their normal tasks.

Bronchitis↗
PubMed1984

Clinical, pathologic, and ultrastructural features of situs inversus and immotile-cilia syndrome in a dog.

Situs inversus, rhinitis, and bronchitis were diagnosed in a 7-month-old male Golden Retriever. Electron microscopic examination of tracheal and bronchial biopsy specimens revealed 9% of the cilia with abnormal axonemal pattern and 1.2% with a fibrous ring between the circle of microtubular doublets and the cell membrane. A permanent response to treatment with antibiotics was not obtained and the dog was euthanatized. At necropsy the thoracic and abdominal organs were found to be in reversed position. Microscopic examination revealed evidence of chronic bronchitis as well as cystic and distended distal tubules of the kidneys. Foci of fibrosis were observed in the renal cortex. The diagnosis was immotile-cilia syndrome.

Animals↗
PubMed1984

Ultrastructural, cellular, and clinical features of the immotile-cilia syndrome.

The immotile-cilia syndrome is an autosomal recessive disease of the microtubules of ciliated cells and spermatozoa, and possibly also of neutrophil leukocytes; it affects approximately 1 in 20,000 people. A variety of aberrations in the axonemal microtubular apparatus has been observed. The most common is deficiency of dynein-arms, which leads to immotility or erratic movement of spermatozoa and respiratory tract cilia. The result is male sterility, and chronic or recurrent respiratory tract infections and bronchiectasis due to absence of mucociliary clearance. In addition, 50% of the persons have situs inversus and hence Kartagener's syndrome.

Chronic Disease↗
PubMed1984

Glycocalyx and glycocalyceal bodies in the respiratory epithelium of nose and bronchi.

The goblet cells of the ciliated respiratory epithelium of the human nose and bronchi and the trachea and bronchi of rabbit, rat, and dog have been investigated with respect to their glycocalyx. The human respiratory epithelium and some of the animal epithelia were found to contain so-called glycocalyceal bodies, i.e., spherical bodies or vesicles with a diameter of about 500 A. These bodies resemble those of the absorptive cells in the human colon and rectum, indicating a close similarity between these two cell types. The presence of such bodies and of prominent microvilli with a core structure has been regarded as diagnostic of primary colorectal carcinoma, but such may also be derived from the respiratory epithelium. The number of glycocalyceal bodies and the prominence of the glycocalyx differ from one goblet cell to the other in the epithelium and are hence properties of the individual cells. There are great species-specific differences with respect to the glycocalyceal bodies; thus, the rat has such bodies in brush cells rather than in goblet cells. Evidence is presented that glycocalyceal bodies are real structures rather than artefacts, but their function(s) remains unknown.

Animals↗
PubMed1983

The spermatozoon of Myzostomum cirriferum (Annelida, Myzostomida).

The Myzostomum spermatozoon has several unique features: The chromatin material is condensed into a variable number of dense balls (usually 42); there is an incomplete myelin-like cover rather than a regular nuclear envelope; a palisade of microtubules surround two mitochondria which extend along the 30-microns-long cell body; an axoneme of the 9+0 formula originates at one end of the cell body, runs intracellularly for a short distance (less than 1 micron), then continues outside the cell body although attached to it by means of a "flagellum-cell body junction," which consists of two sets of strands connecting the membrane of the flagellum to that of the cell body. Two "dorsal rods" in the microtubular palisade evidently are connected to these strands. The flagellum also has a free portion (around 70 microns) which terminates in a pointed spine, called the "sting." No typical centriole and no acrosome have been found. The spermatozoon usually swims with flagellum foremost but may reverse the direction. The cell body also undulates but with an independent wavelength. Presumably some of these peculiarities are specializations for locomotion within body tissues rather than in water; Myzostomum has "dermal copulation."

Animals↗
PubMed1983

Ultrastructural basis for ciliary motility.

The axoneme of a cilium or a sperm tail is a machinery of great complexity. The mechano-chemical work is exerted by the dynein arms and brings about a sliding of the microtubular doublets relative to each other. Nexin links hold the doublets together and restrict the sliding; this makes the cilium bend rather than slide apart. The spokes have several functions and one is to prevent the cilium from becoming buckled when bending. There is a structure called the ciliary necklace in the proximal region of the cilium; this is believed to influence the activity of the cilium by regulating the calcium influx. The two principal pathways, which can be used to explore the ciliary machinery and its many components are (a) "chemical dissection" of the cilium by selectively dissolving the various parts of the machinery and (b) examination of ciliary mutants which can be obtained from experiments with protists or at the investigation of the population attending lung clinics or male fertility clinics as patients. Such human ciliary mutants usually belong to the immotile-cilia syndrome.

Cilia↗
PubMed1983

Acquired ciliary defects compared to those seen in the immotile-cilia syndrome.

An attempt is made to characterize injured cilia and ciliary mutants separately with particular emphasis on human conditions. The usefulness of electron microscopical investigations is stressed. An injury to a ciliated epithelium may very well be restricted to one site in the body and may appear at any stage of life. Typical ciliary mutants, such as are seen in the immotile-cilia syndrome, represent a generalized condition and will be found from the beginning of life. Some types of ciliary defects are relatively unspecific and found after various kinds of insult to the cilia also in the immotile-cilia syndrome; these are: compound cilia, supernumerary microtubules in the axoneme, and loss of cilia or of ciliated cells. Other kinds of ciliary defect seem to be typical of the ciliary mutants: absence of dynein arms, absence of spokes and central sheath, transposition of one of the central microtubules and short central microtubules.

Anesthetics, Local↗
PubMed1983

The immotile-cilia syndrome compared to other obstructive lung diseases: a clue to their pathogenesis.

Twentyfour adults, aged 19-47 years, with congenitally nonfunctioning cilia were investigated by clinical examination, radiography, spirometry, and in most cases by tracheobronchial clearance measurements and ultrastructural examination of respiratory tract cilia and/or sperm tails. They all suffered from chronic bronchitis, rhinitis and sinusitis, and most of them had bronchiectasis and a history of otitis. Most had spirometrically overt obstructive lung disease and four radiological signs of emphysema. Clinical profile, lung function and mucociliary clearance data were compared to corresponding data from samples of patients with other obstructive lung diseases. These comparisons indicate that a long-standing impairment of mucociliary clearance is of pathogenetic importance in common chronic obstructive lung disease associated with chronic bronchitis, but not in emphysema associated with severe alpha 1-antitrypsin deficiency without chronic bronchitis, and not in asthma. In cystic fibrosis and in hypogammaglobulinemia an impaired clearance is not of primary pathogenetic significance but may contribute to the development of obstructive lung disease.

Adult↗
PubMed1983

Male and female infertility problems in the immotile-cilia syndrome.

The immotile-cilia syndrome is a heterogeneous disease. The dynein arms were missing totally or almost totally, and both spermatozoa and cilia were immotile in most cases examined by us. In other cases, the ciliary axoneme displayed other defects and the spermatozoa had motility although restricted; there was no progressive motility. Fourteen men with this syndrome were all sterile. Fifteen women had the syndrome and twelve tried to become pregnant. This had been successful (one, one, and two children) in three cases only. Thus, it appears that female fertility is also impaired in this syndrome, although not completely. No case of ectopic pregnancy has been reported.

Cilia↗
PubMed1983

Measurements of tracheobronchial clearance in patients with immotile-cilia syndrome and its value in differential diagnosis.

Tracheobronchial clearance was studied in twenty patients who fulfilled suggested criteria of the immotile-cilia syndrome and in eight other patients suspected of suffering from the syndrome, but who did not fulfill the criteria. Clearance was studied using 6 micrometers teflon aerosol particles tagged with 99mTc and external measurement of the radioactivity. The criteria were based on combinations of a typical history of bronchitis, rhinitis and sinusitis since childhood, hereditary data, situs inversus, sperm immotility and characteristic defects of respiratory tract cilia and sperm tails. All patients who fulfilled the criteria had an extremely slow, probably no, tracheobronchial mucociliary clearance, whereas all those who did not fulfill the criteria had some clearance. Evidently the diagnosis immotile-cilia syndrome can be obtained without clearance measurements in typical cases, but such measurements are of value in atypical cases, especially for excluding the syndrome.

Adult↗