Amorphous Extracellular Material Research Articles

Spatial relationship of the vaginal microflora to the vaginal epithelium of female rats: scanning electron microscopy.

The vaginal mucosa of ovariectomized female rats has been examined by scanning electron microscopy before and after estrogen [1,3,5(10)-estratriene-3,17beta-diol] treatment. Without estrogen stimulation vaginal colonization is minimal and the epithelium is characterized by a layer of epithelial cells covered with small microvillous-like projections. Progressive changes that were consistent with estrogenic cytoproliferative effects were seen after estrogen treatment. By post-treatment day 3 bacterial colonization was maximal and the epithelium was comprised of flat squamous cells that tended to become detached from the underlying tissue layers. Bacteria were seen in association with the intercellular borders of this tissue and occurred singly or as microcolonies. No distinct physical attachment structures were identified, although an amorphous extracellular material that may serve to attach the bacteria to the squamous epithelial cells was frequently seen.

Fine structure of the avian muscle spindle capsule.

The capsule of the muscle spindle from the anterior and posterior latissimus dorsi muscles of the adult domestic chicken has been studied with the electron microscope. As in other species, two distinct portions of the spindle capsule are distinguished: an outer capsule and an inner capsule. The outer capsule is structurally similar to and continuous with the perineural epithelium. Outer capsule cells are noted by the abundance of pinocytotic vesicles and a network of 6-7-nm microfilaments. The disposition of these microfilaments is circumferential with respect to the longitudinal axis of the spindle. It is proposed that they may provide a contractile mechanism for the capsule which may be related to the over-all functioning of the spindle during movements of the muscle. The inner capsule is composed of a contiguous network of cells possessing long cytoplasmic processes which envelop the intrafusal fibers and their nerve endings in sensory equatorial regions of the spindle. These cells may elaborate the fibrillar and amorphous extracellular material found in periaxial spindle space. They also possess modified cilia with a "9+0" microtubular pattern. It is suggested that these cilia may behave as sensory transducers, relating fluid changes in the periaxial space to the intrafusal fiber nerve endings. Capillaries of the non-fenestrated variety commonly traverse the outer and inner portions of the capsule and are usually completely surrounded by tenuous overlapping processes of inner capsule cells. These findings suggest that the spindle capsule plays a role as a metabolically-active diffusion barrier to the entrance of substances from the external milieu.

Cytodiagnosis of rheumatoid pleural effusions.

The stained smears of the deposits from one pericardial and 19 pleural effusions complicating rheumatoid arthritis were examined. On the basis of clinical and biochemical evidence it was considered that in six cases the effusions were due to the rheumatoid disease while in a further nine cases the association was considered likely. In the remaining five cases the association was considered to be due to chance as other causes for the effusions were diagnosed. On cytological examination, seven cases showed a characteristic picture of degenerating polymorphs with amorphous extracellular material and epithelioid cells many of which were multinucleate. Five others contained similar amorphous material without epithelioid cells; of these two had many plasma cells and a third numerous macrophages probably containing ;droplets' of rheumatoid factor complex. Thus in 12 of 15 cases a definite diagnosis of rheumatoid effusion could be made. In the remaining five cases cytological examination confirmed that the effusions were unrelated to the rheumatoid disease.The extracellular material gave a non-specific fluorescence with labelled anti-gamma globulin antisera, and since this reaction was not seen in control pleural fluid deposits, or with preparations of fibrin, it may have a confirmatory value. It is concluded that in many cases reliable cytological evidence can be found to confirm or refute a diagnosis of rheumatoid pleural or pericardial effusion. This may be helpful in the management of the rheumatoid disease.

Changes in thrombocyte ultrastructure during clot retraction.

ABSTRACT The contraction of the entire thrombocyte appears to be a primary factor in the retracting mechanism of dogfish (Musteltis canis) in vitro blood clots. Microtubules probably account for the condensation and lobation of the nucleus, and the impetus for cytoplasmic contraction appears to be dependent upon the grouping of microfibres of dimensions difficult to measure. These microfibres show a striking resemblance to materials stored within adjacent vesicles. A second type of fibre (60 A in diameter) extends from the bases of pseudopods into the adjacent matrix. There also appears to be partial engulfment of an extracellular amorphous material by the plasma membrane. The ultrastructure of the thrombocyte during clot retraction shows some striking similarities to the mammalian platelet under similar conditions, and leads one to believe a phylogenetic relationship exists between these haemostatic cells.