A morphometric comparison of subcellular structures between primary breast tumors and their nodal metastases.

A morphometric study of subcellular structures in human primary breast tumors (of the ductal infiltrating type) and their synchronous lymph node metastases was carried out using planimetry and stereology. Each primary neoplasm was compared separately with its axillary metastatic growth in order to detect differences in the quantitative estimates of their subcellular components. A set of 24 morphometric parameters was used to quantitatively describe each neoplastic cell profile. Although some subcellular parameters showed significant differences between the cells of a primary tumor and its metastases, no parameter was found to be consistently altered in all cases. No consistent increase or decrease in the values of the affected parameters was observed in the metastases. More than being due to the expression of a biologically variant (more-or-less differentiated) metastatic phenotype, the differences in stereologic parameters detected in metastatic cells appear to reflect the existence of different functional states of the same cell type.     

Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin

doi:10.1111/j.1741‐2358.2009.00333.x
Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin Objective: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). Background: Controversial findings have shown that mechanical or chemical changes in ridge‐lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. Materials and methods: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74°C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross‐speed of 1 mm/min. Collected data were submitted to anova and Tukey’s test (α = 0.05). Results: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non‐microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. Conclusion: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.     

Differential effects of cAMP and cGMP on in vitro epidermal cell growth.

Primary keratinocyte cultures free of dermal fibroblasts were used to investigate the effect of varying cyclic AMP (cAMP) concentrations on epidermal cell function. Addition of 10^?3, 10^?4 or 10^?5 M dibutyryl cAMP to plated cells (day 1) results by day 5 in a dose dependent increase of [³H]TdR incorporation into DNA as determined by increases in both the labeling index and incorporation of ³H label into an isolated DNA fraction. 8-Bromo cAMP, another cAMP analogue, likewise induced keratinocyte proliferation. The proliferative response was dose and time dependent, and 5- to 6-fold increases in ³H label incorporated into DNA were seen at day 6, 8 and up until day 15 of culture. Moreover, elevation of cellular cAMP by addition of cholera toxin, an irreversible stimulator of adenylate cyclase, also demonstrated a time dependent stimulation of [³H]TdR uptake into DNA and increased the labeling index. Specific histochemical staining for keratinaceous protein (Kreyberg technique) demonstrated that elevated cAMP levels also enhance the production of specialized (differentiated) epidermal cells. Determination of the level of cAMP and cyclic GMP (cGMP) by RIA of partially purified fractions of the cultures revealed that addition of 8-bromo cAMP or cholera toxin to the cultures increased the levels of cAMP but not of cGMP. Addition of 8-bromo cGMP to the keratinocytes on day 1 at concentrations of 10^?6, 10^?7 or 10^?8 M had no effect on culture proliferation on days 4, 6 and 8, although qualitative changes in the electron microscopic pattern of the culture stratification and specialization were observed. The results indicate (1) both large and moderate increases in cellular cAMP levels induce keratinocyte culture proliferation and specialization in the absence of fibroblasts or dermal influences, (2) the quantitative enhancement of keratinocyte growth and specialization occurs without apparent participation of cGMP, (3) cGMP may be a qualitative effector of epidermal cell differentiation.     

Choricotyle anisotremi n. sp. (Monogenea: Diclidophoridae) parasitic on Anisotremus scapularis (Tschudi) from the northern Chilean coast

Choricotyle anisotremi n. sp. is described from the gills and on the inner surface of the operculum of Anisotremus scapularis (Pomadasyidae) from the Chilean coast. Distinct characteristics of the new species are: presence of an oval accessory sclerite on the inner quadrant of the clamp adjacent to the accessory sucker; 12 genital hooks; short and stout peduncles, the last pair of which are closely apposed; a lobed seminal receptacle; and a fan-like posthaptor without a terminal lappet.     

Aggregate-formation by Clostridium butyricum

Summary Clostridium butyricum was grown in a glucose-limited chemostat culture at a dilution rate of 0.1 h^–1 at pH 6.0. With 0.9% w/v input glucose in the medium the cells were found to grow in suspension and glucose was fermented completely to acetate and butyrate. An increase in the input concentration of glucose resulted in increased concentrations of end-products, but not all extra glucose was consumed. It could be demonstrated that this was due to a lowering of the maximal growth rate by elevated levels of butyric acid. However, prolonged growth in the presence of high glucose concentrations led to an increase in biomass. This was caused by the selection of a variant that was less sensitive to butyrate. This variant was able to form aggregates in an anaerobic gas-lift reactor at high dilution rates. Inoculation of these aggregates in a conventional chemostat culture with high glucose input resulted in an aggregated culture that remained stable for at least 6 months, and in which all glucose was consumed. Whether the organisms grew in suspension or in aggregates was found to be determined by the concentration of butyrate. The isolation of aggregate-forming variants from chemostat cultures leads to a very simple and new type of immobilization technique.Offprint requests to: G. R. Zoutberg     

Replacement of potassium ions by ammonium ions in different micro-organisms grown in potassium-limited chemostat culture

The biomass concentration extant in potassiumlimited cultures of either Klebsiella pneumoniae or Bacillus stearothermophilus (when growing at a fixed temperature and dilution rate in a glucose/ammonium salts medium) increased progressively as the medium pH value was raised step-wise from 7.0 to 8.5. Because the macromolecular composition of the organisms did not vary significantly, this increase in biomass could not be attributed to an accumulation of storage-type polymers but appeared to reflect a pH-dependent decrease in the cells' minimum K⁺ requirement. Significantly, this effect of pH was not eviden with cultures in which no ammonium salts were present and in which either glutamate or nitrate was added as the sole nitrogen source; however, it was again manifest when various concentrations of NH₄Cl were added to the glutamate-containing medium. This suggested a functional replacement of K⁺ by NH ₄ ⁺ , a proposition consistent with the close similarity of the ionic radii of the potassium ion (1.33 Å) and the ammonium ion (1.43 Å). At pH 8.0, and with a medium containing both glutamate (30 mM) and NH₄Cl (100 mM), cultures of B. stearothermophilus would grow without added potassium at a maximum rate of 0.7 h^-1. Under these conditions the cells contained maximally 0.1% (w/w) potassium (derived from contaminating amounts of this element in the medium constituents), a value which should be compared with one of 1.4% (w/w) for cells growing in a potassiumlimited medium containing initially 0.5 mM K⁺. Qualitatively similar findings were made with cultures of K. pneumoniae; and whereas one may not conclude that NH ₄ ⁺ can totally replace K⁺ in the growth of these bacteria, it can clearly do so very extensively.     

Hydrocortisone regulates arylsulfatase A (cerebroside-3-sulfate-3-sulfohydrolase) by decreasing the quantity of the enzyme in cultures of cells dissociated from embryonic mouse cerebra

Previous work from our laboratory (Biochem. J. 219:689–697 (1984) had shown that hydrocortisone stimulated the net accumulation of the myelin-specific sulfolipid in cultures of cells dissociated from embryonic mouse cerebra. This accumulation caused by hydrocortisone was shown to be due to a decrease of sulfolipid degradation by arylsulfatase A (ASA) and not due to a stimulation of its synthesis by a sulfotransferase. Both ASA activity and the turnover of sulfolipid were decreased by hydrocortisone to 60–62% of untreated cells. In current work the same decrease in enzyme activity was obtained and enzyme linked immunosorbent assays demonstrate that hydrocortisone decreased the number of ASA protein molecules to 61% of untreated cells [(-)hydrocorcortisone 0.31±0.06 ng ASA/g protein; (+)hydrocortisone: 0.18±0.04 ng ASA/g protein]. This decrease in the number of ASA molecules correlates well with the decrease in both the enzyme activity and the sulfolipid turnover, which suggests that the major mode of inhibition of ASA activity by hydrocortisone involves a decrease in the concentration of ASA in the cells rather than some other mechanism of inhibition.The material in this paper has been included in a dissertation submitted by A.J.M. in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Temple University.     

The cytotaxonomy ofEmilia spp. (Asteraceae: Senecioneae) occurring in Brazil

Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.     

Cytochemical evaluation of gamma-glutamyl-transpeptidase activity in cervical smears

The cervicovaginal smears of 43 patients attending an outpatient service for early cancer detection were cytochemically studied for the presence of gamma-glutamyl-transpeptidase (GGT) in epithelial cells. This was done in order to evaluate such an enzyme phenotype as a marker for cancer development. The results showed that 70% of the 38 patients with a cytologic diagnosis of "inflammatory" or preneoplastic/neoplastic conditions had GGT-positive cells in their smears. None of the five cytologically normal cases showed any epithelial cells with GGT activity. Although most of the GGT-positive cells were metaplastic, some morphologically normal, dysplastic or neoplastic cells also expressed the enzyme. The data suggest that cytochemically detectable transpeptidase activity appears whenever alterations of the normal epithelial microenvironment occurs, but is not necessarily linked to the carcinogenic process. Therefore, cytochemically GGT-positive cells should not be used as an indicator of neoplastic transformation of the cervical epithelium.