Multiple mitochondrial alterations in a case of myopathy.

Mitochondrial alterations are the most common feature of human myopathies. A biopsy of quadriceps muscle from a 50-year-old woman exhibiting myopathic symptoms was examined by transmission electron microscopy. Biopsied fibers from quadriceps muscle displayed numerous subsarcolemmal mitochondria that contained crystalloids. Numbering 1-6 per organelle, these consisted of rows of punctuate densities measuring ∼0.34 nm; the parallel rows of these dots had a periodicity of ∼0.8 nm. The crystalloids were ensconced within cristae or in the outer compartment. Some mitochondria without crystalloids had circumferential cristae, leaving a membrane-free center that was filled with a farinaceous material. Other scattered fibrocyte defects included disruption of the contractile apparatus or its sporadic replacement by a finely punctuate material in some myofibers. Intramitochondrial crystalloids, although morphologically striking, do not impair organelle physiology to a significant degree, so the muscle weakness of the patient must originate elsewhere.

Fusion of the envelope of mucous droplets with the luminal plasma membrane in acinar cells of the cat submandibular gland.

The release of mucus from acinar cells of the cat submandibular gland was examined by electron microscopy. The limiting membrane of mucous droplets fuses with the luminal plasma membrane to form a five-layered contact. This is converted to a three-layered membrane (unit membrane) by avulsion of the plasmalemma. Attenuation and rupture of this membranous barrier permits the contents of the mucous droplets to flow into the lumen.

Unusual filamentous structures in the paragonia of male Drosophila.

Drosophila paulistorum is a complex of five incipient species which when crossed produce sterile hybrid males and fertile females. Sterility of the male progeny can sometimes be induced by injecting females of one strain (Mesitas) with a homogenate of males of another strain (Santa Marta) or of hybrids between these strains, and then crossing the recipient females to Mesitas males. Filamentous structures have been found in cytoplasmic vacuoles in paragonial cells in males of these and other similar strains and their hybrids. These structures, which contain RNA, possess a helical substructure and resemble certain viruses. Large filamentous structures found in the lumen of the paragonia are also described.

Riboflavin and mouse hepatic cell structure and function. II. Division of mitochondria during recovery from simple deficiency.

Mice which had been on a riboflavin-free diet for 6-8 wk were given daily intraperitoneal injections of riboflavin. The hepatic mitochondria, which in the deficient animals were greatly enlarged, were restored to normal dimensions within 3 days. Normalization of the mitochondrial population was brought about by division of the giant organelles. Dividing mitochondria were characterized by a membranous partition separating the inner compartment into two distinct chambers. Such organelles showed varying degrees of pinching at the level of the partition. The most common site of partition formation was at the base of a small mitochondrial bud. During the 1st day of recovery, dividing mitochondria were so common that they could be easily found in mitochondrial pellets. Injection of riboflavin into normally nourished mice also produced an apparent increase in the frequency of dividing mitochondria in the liver cells.

Proteinases of Pseudomonas aeruginosa evoke mucin release by tracheal epithelium.

We have determined the potential of exoproducts from pathogenic bacteria to stimulate the release of high molecular weight mucins from goblet cells of airway epithelium in a rabbit tracheal explant system. Culture supernatants from proteolytic strains of Pseudomonas aeruginosa and Serratia marcescens, but not supernatants from a number of non-proteolytic strains, released mucins from goblet cells. Highly purified elastase and alkaline proteinase from P. aeruginosa stimulated goblet cell mucin release in a dose-dependent fashion. Lipopolysaccharide, exotoxin A, and alginate of P. aeruginosa did not possess mucin release properties. Proteolytic activity was required for mucin release by P. aeruginosa elastase, but such release in goblet cells was not mediated by cyclic AMP. Morphologic studies suggested rapid release of mucins from goblet cells was response to elastase by a process resembling apocrine secretion. Several nonbacterial proteinases mimicked the effect of Pseudomonas proteases. These studies provide support for the hypothesis that bacterial and other play a role in the pathogenesis of mucus hypersecretion in acute and chronic lung infections.

High resolution scanning electron microscopy of the intracellular surface of intercalated disks in human heart.

The three-dimensional architecture of human cardiac intercalated disks was examined by high resolution scanning electron microscopy of osmium-macerated specimens. This methodology permits viewing of in situ intercalated disks from a vantage point inside individual cardiomyocytes. The erose nature of these structures was rendered in stark relief. Areas covered with clusters of particles were present on some membranous projections--these may represent a combination of desmosomes and fasciae adherentes. On the other hand, areas devoid of particles may correspond to gap junctions.

Forms of a self associating autoantibody complex between a monoclonal human IgG1 and human serum albumin.

The mode of association of an unusual human autoantibody complex, composed of a monoclonal immunoglobulin, Tu IgG, and human serum albumin was investigated. A crystalline complex forms from these components in the cold and we have shown that it consists of IgG and albumin in a 1:2 molar ratio [Jentoft et al., Biochemistry 21, 289-294 (1982)]. The crystalline complex was analyzed by electron microscopy and the soluble natural complexes (formed by dissolving the crystals at 20 degrees C) were studied by sedimentation velocity. The sedimentation studies demonstrated that the soluble Tu IgG-albumin complexes are in equilibrium with free Tu IgG and albumin molecules and that the major soluble sedimenting species has a S20,w value of 12.5S. At a constant concn of complex, the size of the sedimenting complex can be reduced by lowering the pH, increasing the ionic strength, or adding CaCl2, citrate, ascorbate or urea. These intermediate, soluble forms have S20,w values that are consistent with 1:1 and 1:2 Tu IgG-albumin complexes. Parameters of repeat distances and angles that were obtained from electron micrographs of the crystalline form of the Tu IgG-albumin complex were used to propose a model for the 12.5S species and were also incorporated into a three-dimensional model for the complex. The 12.5S complex is proposed to form by dimerization of the 1:2 Tu IgG-albumin complex via interactions of albumin with the Fc region of the antibody. The 12.5S dimer may be the nucleating species for subsequent rapid associations that lead to spontaneous formation of crystals. In the proposed model for the Tu IgG-albumin crystals, the angle between the Fab arms of each Tu IgG molecule is 90 degrees, the antigenic determinant on the albumin is located near one end of the long axis of the cylindrical molecule, the site of interaction with Fc is located at the other end of the cylinder, and the CH3 domain of the IgG contains the binding site for albumin that is responsible for the formation of the dimeric 12.5S species. A series of sedimentation velocity experiments suggest that the association between the CH3 domain of IgG and albumin requires the prior formation of the antibody-antigen complex.

Crystalloids in the excretory ducts of the accessory submandibular gland of the long-winged bat, Miniopterus magnator.

Cytoplasmic crystalloids are abundant in the excretory ducts of the accessory submandibular gland of the long-winged bat, Miniopterus magnator. The crystalloids, which always lack a membranous enclosure, may have an intricate silhouette. They consist of parallel linear densities with a 12.5 nm periodicity. These densities actually may be thin-walled tubules. In some crystalloids, intersecting subcrystalloids produce a complex pattern of decussate densities. In a few rare instances, continuities were detected between a crystalloid and a smooth-surfaced cisternal element. In other mammalian species, similar crystalloids connected to smooth endoplasmic reticulum play a role in steroid metabolism. We postulate that the ductular crystalloids in M. magnator might be involved in production of a factor that influences mating behavior.

Biodegradable fibres spun from poly(lactide) generated by reactive extrusion.

Poly(lactide) (PLA) was spun both in a high speed spinning process with take-up velocities of 1000-5000 m min(-1) and in a spin drawing process at draw ratios of 4-6. The effect of the melt spinning conditions on the development of the structural hierarchy in the fibres and the relations to the textile physical properties were investigated. The PLA fibres were characterised with regard to the degree of crystallinity by DSC and WAXS, the orientation by WAXS and birefringence, and the stress-strain behaviour. The maximum physical break stress and the E-modulus observed in the spin drawn fibres were about 490 MPa and 6.3 GPa, respectively, at an elongation at break of 30%. The PLA was a copolymer of L-lactide (92 wt.%) and meso-lactide (8 wt.%) and was generated by reactive extrusion polymerisation. The PLA virgin pellets were analysed regarding their degradation during the spinning processes. Their thermal and rheological properties were determined by DSC and dynamic rheological measurements, respectively, to derive suitable parameters for the melt spinning processes.

Salivary gland changes in disease.

Ultrastructural alterations occurring in human salivary glands as a result of a variety of diseases are described. Major changes in these organs in cases of cystic fibrosis are probably the result of duct blockage, as indicated by study of chronically inflamed salivary glands. A new disease of salivary glands is reported in which parotid serous granules are distorted by bundles of fine filaments, which may be due to the untoward polymerization of a secretory protein, perhaps proline-rich protein. Finally, a clear-cell adenocarcinoma of palatine gland origin is described in which the nuclei display complex pseudoinclusions and the cytoplasm contains numerous herpes-type viruses.

Ultrastructure of the secretory cells of the submucosal glands in the human maxillary sinus.

Tissue samples obtained from the lateral wall of the maxillary sinuses of five patients were examined by light microscopical, histochemical, and ultrastructural techniques. Submucosal glands were tubulo-alveolar mixed glands. The acini consisted of either all serous or all mucous cells, or a mixture of both. Serous granules were stained by toluidine blue, or by hematoxylin and eosin (H and E), but showed little or no reaction with periodic acid-Schiff (PAS) or Alcian blue. Mucous granules were pale in toluidine blue or H and E preparations, and consisted primarly of acid mucosubstances, as demonstrated by their staining reaction with PAS and Alcian blue. At the electron microscope level, the serous granules were either homogeneously dense, or showed a substructure consisting of at least two layers of distincly different electron-opacity. Typical mucous droplets consisted of a fibrillar network dispersed in a translucent matrix. A second secretory product was present in the mucous cells in the form of elongated, membrane-bounded structures containing numerous parallel filaments, which measured about 55 A in diameter. The mucous droplets and the filamentous bodies appear to arise from the opposite faces of the Golgi complex in the mucous cells. The filamentous bodies showed a pronounced tendency to fuse with the mucous droplets. All acini were surrounded by a well-defined myoepithelial layer and contained intercellular nerve terminals.

Ultrastructure of the main excretory duct of the cat submandibular gland.

The main excretory ducts (MED's) from the submandibular gland of adult cats were examined by electron microscopy. The ducts consisted of a pseudostratified epithelial lining surrounded by abundant connective tissue and numerous, small, longitudinally-oriented blood vessels. The taller epithelial cells were closely coherent, without the luminal clefts between adjacent cells that are characteristic of rat MED's. In the cat, these cells lacked basal membrane specialization, but showed considerable lateral interdigitation. Some microvilli were present on the apical surface. In a few rare cells, the luminal surface bore cilia of typical appearance. The smaller, pyramidal basal cells had irregular basal surfaces that gave rise to one or more long cytoplasmic processes. The basal surface of the pyramidal cells was studded with hemidesmosomes. The cytoplasms contained abundant tonofilaments, which sometimes aggregated in prominent perinuclear bundles. Occasional goblet cells were present in the duct wall. MED's perfused either in situ or in a perfusion chamber with Locke's solution also were studied. Even after perfusion of 160 minutes duration, the ultrastructure of the ductal epithelium showed remarkably few alterations. The MED model system thus remains stable long enough to carry out physiological experiments which may produce ultrastructural alterations.

Histology and histochemistry of the parotid and the principal and accessory submandibular glands of the little brown bat.

The parotid and the principal and accessory submandibular glands of the little brown bat. Myotis lucifugus (Vespertilionidae), were examined using light microscopy and staining methods for mucosubstances. The parotid gland is a compound tubuloacinar seromucous gland. Parotid gland secretory cells contain both neutral and nonsulfated acidic mucosubstances. The principal and accessory submandibular glands are compound tubuloacinar mucus-secreting glands. They contain somewhat atypical mucus-secreting demilunar cells that often appear to be interspersed between mucous tubule cells. The mucous tubule cells in both the principal and accessory submandibular glands contain sulfonmucins. Demilunar cells of the principal submandibular gland contain moderate amounts of nonsulfated acidic mucosubstances, but the corresponding cells of the accessory submandibular gland contain considerable neutral mucosubstance with very little acid mucosubstance. Intercalated ducts composed of cuboidal or low columnar epithelial cells are present in all three glands. Striated ducts in all glands are composed of columnar cells whose apices bulge into the ductal lumina. Excretory ducts are composed of simple columnar epithelium, with occasional basal cells that suggest a possible pseudostratified nature. The cells of the excretory ducts also have bulging apices. All duct types contain apical cytoplasmic secretory material that is a periodic acid-Schiff positive, neutral mucosubstance. Ductal apical secretory material is more evident in intercalated and striated ducts than in excretory ducts.

Ultrastructure of chronically inflamed human submandibular glands.

The structure of chronically inflamed submandibular glands from four patients was examined by electron microscopy. The patients were free of the sicca syndrome and lacked other symptoms of Sjögren's syndrome or related autoimmune diseases. The affected glands were characterized by a reduction in acinar elements, by ductular proliferation and hyperplasia, and by large numbers of inflammatory cells in the stroma. This study indicates that many of the ultrastructural changes in salivary glands previously attributed to autoimmune diseases may also occur in patients who are free of such afflictions but whose salivary glands have undergone intermittent obstruction or infection.

Giant secretory granules in the ducts of the parotid and submandibular glands of the slow loris.

The parotid and submandibular glands of a slow loris, a rare Southeast Asian primate, were obtained after the head had been perfused by fixative for a study of the brain. These tissues were processed by conventional means for electron microscopy. Glands also were obtained at autopsy from 2 other lorises, fixed by immersion in formalin, and subjected to a battery of tests for glycoconjugates. In the parotid gland, a short segment of the proximal striated duct lacks both basal striations and any sign of secretory activity. The major portion of the striated duct consists of tall cells that contain a spectrum of secretory granules, some larger than the nuclei (many granules are > 9 mum in diameter). These granules, which are delimited by a single membrane, are capable of chain exocytosis. Many of the giant granules have bundles of cytofilaments (4.5-6.5 nm) in apparent association with their surface. Occasional cells contain numerous small granules. Duct cells with or without granules lack basal striations. The granules contain neutral glycoconjugates but no acidic glycoconjugates. Some, but not all, interlobular excretory ducts also have secretory granules that run the gamut from tiny to giant. Exactly the same situation occurs in the submandibular gland. Unlike other primates, which may have duct cells that contain only a few tiny granules in their apices, the cells in both the striated and excretory ducts in the slow loris appear to be specialized for secretion rather than for transport. The biofunction of the giant granules is unknown.

Cytomegalovirus in the principal submandibular gland of the little brown bat, Myotis lucifugus.

In the course of a large scale study of salivary gland ultrastructure in chiropterans, enlarged cells infected with numerous virus particles were encountered in some acinar cells in the principal submandibular glands of two of 34 little brown bats (Myotis lucifugus). The characteristic morphology of the viruses, together with the cytomegaly that they induced, led to their identification as cytomegalovirus (CMV). In a reversal of the situation in other animal species, bat virus particles within cytoplasmic vacuoles lacked capsomeres, whereas the latter were prominent in particles free in the cytosol. The generally accepted schemes for CMV production cannot explain this seemingly aberrant morphology. This report extends to four the number of mammalian orders in which CMV has been documented by means of electron microscopy as occurring in salivary glands.

Symbiotic bacteria in the accessory submandibular gland of the club-footed bat, Tylonycteris pachypus.

The lumina of the secretory endpieces and, to a lesser extent, of the duct system of the accessory submandibular gland of the club-footed bat, Tylonycteris pachypus, contain numerous rod shaped bacteria. Despite their abundance, these microbes do not evoke an inflammatory response by the glands. The major submandibular gland, as well as the other major salivary glands in these exotic animals contain no bacteria whatsoever. It is concluded that the bacteria in the accessory submandibular gland are symbionts, and that they may play a role in digestion or in the social behavior of their host organisms.

Cytomegalovirus in the parotid gland of a slow loris, Nyctecibus coucang.

Sporadic enlarged cells with both nuclear and cytoplasmic viruses were found in the intralobular ducts of the parotid salivary gland of an adult female slow loris; these ducts are homologous to striated ducts in the salivary glands of other primates. The duct cell nuclei contained reticular inclusions and virions in all stages of development. Cytoplasmic virions were, in almost every case, confined to vacuoles; only a very few were free in the cytosol. The viruses conformed in ultrastructure to that of cytomegaloviruses described in other species. This may be the first observation by electron microscopy of in situ cytomegaloviruses in the salivary glands of a nonhuman primate.