Ultrastructural responses by Golgi apparatus of rat submandibular gland to beta-adrenergic, alpha-adrenergic, and cholinergic stimulation

Rat submandibular gland tissue pieces were stimulated in vitro for 30 min with a beta-adrenergic agent or a cyclic AMP analog to stimulate protein secretion, or with alpha-adrenergic or cholinergic agents or a Ca2+ ionophore to stimulate fluid secretion. Acinar cells were examined by transmission electron microscopy. In control tissue, acinar cells showed little evidence of secretory activity. The Golgi apparatus was sparse and was associated with a few small, immature secretory granules with fine fibrillar contents. Following secretory granule discharge stimulated by isoproterenol or dibutyryl cyclic AMP, acinar cells were constricted, and had extensive basolateral membrane folding and tightly packed rough endoplasmic reticulum. Golgi complexes were prominent and had multiple small granules with filamentous contents. After stimulation of fluid secretion by alpha-adrenergic agents (epinephrine, phenylephrine), or cholinergic agents (acetylcholine, carbachol, pilocarpine), or a Ca2+ ionophore (A23187), the Golgi apparatus had compact concave cisternae enclosing aggregates of tubulovesicles. Acinar cells were distended, basolateral membranes were expanded, and rough endoplasmic reticulum was dilated and vesiculated.     

Tuning of innate immunity and polarized responses by decoy receptors

After the identification of the interleukin (IL)-1 type II receptor as the prototype, decoy receptors have been identified for a number of members of the IL-1/IL-18, TNF, IL-10 and IL-13 receptor families. Moreover, the silent receptor D6 is a promiscuous decoy and scavenger receptor of inflammatory chemokines. The IL-1 decoy receptor is regulated by pro- and anti-inflammatory signals and its levels may serve as a readout of the activation of anti-inflammatory pathways, for instance by glucocorticoid hormones. Decoy receptors represent a strategy to tune inflammatory and polarized adaptive responses.     

Cryptococcus neoformans var. neoformans (serotype D) strains are more susceptible to heat than C. neoformans var. grubii (serotype A) strains

Cryptococcus neoformans var. neoformans (serotype D) and C. neoformans var. grubii (serotype A) differ in geographic prevalence and dermatotropism, with C. neoformans var. neoformans strains being more prevalent among isolates from temperate countries as well as from skin infections. Analysis of 19 strains from each serotype revealed wide variation in thermal susceptibility, with C. neoformans var. neoformans strains being more susceptible, on average, to heat killing. The results suggest a consistent explanation for the geographic differences between serotype A and D strains and for the dermatotropism of serotype D strains.     

Interstitial deletion of 20q in a patient with Waldenström macroglobulinemia following chemotherapy

A 76-year-old male with a history of renal insufficiency was found to have anemia, an IgM kappa paraprotein on serum immunofixation studies, absence of lytic bone lesions, and findings in the bone marrow consistent with Waldenstr?m macroglobulinemia (WM). Cytogenetic studies including fluorescence in situ hybridization (FISH) on the post-treatment bone marrow revealed the karyotype 46,XY,del(20)(q13.1q13.3). Less than 70 cases of karyotypic abnormalities in patients with WM have been reported, which have shown no abnormalities specific to WM. Monosomy or trisomy of chromosome 20 has been reported in approximately eight cases, but to our knowledge this is the first case report of an interstitial deletion of 20q, confirmed by FISH using chromosome 20 subtelomeric specific probes. Interstitial deletions of 20q are known to occur in polycythemia vera and other hematological malignancies, especially those of myeloid origin.     

Identification of an inducible bacteriophage in a virulent strain of Streptococcus suis serotype 2

Streptococcus suis infection is considered to be a major problem in the swine industry worldwide. Most virulent Canadian isolates of S. suis serotype 2 do not produce the known virulence markers for this pathogen. PCR-based subtraction hybridization was adapted to isolate unique DNA sequences which were specific to virulent strains of S. suis isolated in Canada. Analysis of some subtracted DNA clones revealed significant homology with bacteriophages of gram-positive bacteria. An inducible phage (named Ss1) was observed in S. suis following the incubation of the virulent strain 89-999 with mitomycin C. Phage Ss1 has a long noncontractile tail and a small isometric nucleocapsid and is a member of the Siphoviridae family. Ss1 phage DNA appears to be present in most Canadian S. suis strains tested in this study, which were isolated from diseased pigs or had proven virulence in mouse or pig models. To our knowledge, this is the first report of the isolation of a phage in S. suis.     

Tissue invasiveness and non-acidic pH in human candidiasis correlate with "in vivo" expression by Candida albicans of the carbohydrate epitope recognised by new monoclonal antibody 1H4

Background: The morphogenetic conversion between yeast and hyphal growth forms appears to be crucial in the pathogenesis of invasive candidiasis, and can be regulated by environmental signals such as extracellular pH.     

Multiple macrodontic multituberculism

Ekman-Westborg and Julin [1974: Oral Surg 38:217-222], described multiple macrodontia and multituberculism affecting the teeth without other anomalies (E-WJ). We describe a Chilean case in a 12-year-old with the typical dental alterations and with histopathologic findings that include absence of predentin layer and prominent reduced enamel epithelium. E-WJ is not a syndrome and we propose "multiple macrodontic multituberculism" as a better name for this anomaly of uncertain etiology affecting only the crowns of the teeth.     

Solid-phase enzyme immunoassay for the detection of HMG nonhistone proteins in their native structure

The use of purified specific antibodies against HMG1 and HMG17 (high mobility group nonhistone chromosomal proteins), together with a very sensitive solid phase enzyme immunoassay, allows the detection of nanograms of these proteins free in solution or in chromatin native structure, and the measurement of their accessibility. The sensitivity of the assay is comparable to that of the radioimmunoassay, with the advantage of avoiding the handling of radioactive materials.     

Leukemic transformation in patients with the 5q- alteration: analysis of the behavior of the 5q- clones in preleukemic to leukemic phases

Serial cytogenetic studies have been performed in four patients with myelodysplastic syndromes. In all four a 5q- alteration was present, but with a different pattern of presentation. One patient presented 5q- as the only alteration since diagnosis; two patients acquired this alteration during the course of the disease; and the fourth showed a 5q- plus other alterations since the first cytogenetic study. Likewise, three of the four patients showed a clone with trisomy 8 and without 5q-. According to these observations and others from the literature with similar cytogenetic behavior, we have analyzed the following points: 5q- as a primary event and as the only alteration, 5q- as a secondary event, 5q- plus other alterations, and presence of cytogenetically different clones. Analysis of these points suggests that the 5q- alteration can represent an early mutation conferring a slow capacity of expansion to the affected clones, with the possibility of cytogenetic evolution during the progression of the disease (about 30% of the patients). Likewise, the association of trisomy 8 clones with 5q- clones can be a nonrandom event.     

Binding of extracellular matrix proteins to Aspergillus fumigatus conidia.

As detected by confocal immunofluorescence microscopy, binding of fibronectin and laminin appeared to be associated with the protrusions present on the outer cell wall layer of resting Aspergillus fumigatus conidia. Flow cytometry confirmed that binding of laminin to conidia was dose dependent and saturable. Laminin binding was virtually eliminated in trypsin-treated organisms, thus suggesting the protein nature of the binding site. Conidia were also able to specifically adhere to laminin immobilized on microtiter plates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting) with laminin and antilaminin antibody of whole conidial homogenates allowed identification, among the complex array of protein and glycoprotein species, of one polypeptide with an apparent molecular mass of 37 kDa which specifically interacts with laminin. The fact that binding of conidia to soluble or immobilized laminin or fibronectin was inhibited by fibronectin or laminin, respectively, suggests the existence of common binding sites for both ligands on the surface of conidia. Intact conidia were also able to adhere to type I and IV collagen immobilized on microtiter plates; adhesion was found to be dose dependent and saturable. Adhesion to immobilized type I and IV collagen was markedly inhibited by laminin and weakly inhibited by fibronectin. Coincubation of conidia with Arg-Gly-Asp (RGD) peptides caused a dose-dependent decrease in binding of cells to immobilized or soluble fibronectin, yet interaction of cells with soluble or immobilized laminin and type I and IV collagen remained unaffected. Interactions described here could be important in mediating attachment of the fungus to host tissues, thus playing a role in the establishment of the disease.