Intratumor heterogeneity of biomarker expression in breast carcinomas

Small biopsy samples are used increasingly to assess the biomarker expression for prognostic information and for monitoring therapeutic responses prior to and during neoadjuvant therapy. The issue of intratumor heterogeneity of expression of biomarkers, however, has raised questions about the validity of the assessment of biomarker expression based on limited tissue samples. We examined immunohistochemically the expression of HER-2neu (p185^erbB-2), epidermal growth factor receptor (EGFR), Bcl-2, p53, and proliferating cell nuclear antigen (PCNA) in 30 breast carcinomas using archived, paraffin embedded tissue and determined the extent of intratumor heterogeneity. Each section was divided into four randomly oriented discrete regions, each containing a portion of the infiltrating carcinoma. For each tumor, the entire lesion and four regions were analyzed for the expression of these markers. Scores of both membrane and cytoplasmic staining of HER-2neu and EGFR, scores of cytoplasmic staining of Bcl-2, and scores of nuclear staining of both p53 and PCNA were recorded. The intensity of staining and the proportion of immunostained cells were determined. A semiquantitative immunoscore was calculated by determining the sum of the products of the intensity and corresponding proportion of stained tumor cells. We analyzed both invasive (IDC) and in situ (DCIS) carcinomas. The Wilcoxon signed-rank test was used for paired comparisons between overall and regional immunoscores and between overall and regional percentages of stained cells. Spearman's correlation coefficients were used to assess the level of agreement of overall biomarker expression with each of the regions. Generalized linear models were used to assess overall and pair-wise differences in the absolute values of percent changes between overall and regional expression of biomarkers. For IDCs, there were no statistically significant differences in the expression of the biomarkers in terms of either the percentage of cells staining or the immunoscores when comparing the entire tumor with each region except for the lower EGFR expression of arbitrarily selected region 1 and lower p53 expression of region 1 compared to that of the entire tumor section. For DCIS, there were no statistically significant differences in the expression of the biomarkers between the entire tumor and each region except in PCNA of region 2 compared to that of entire tumor section. Positive correlation of immunoscores was observed between the entire tumor and each region as well as across all four regions for IDC. Similar observations were noted with DCIS except for HER-2neu and PCNA. No statistically significant differences were observed in the absolute values of percent changes of biomarker expression between overall and the four regions for both DCIS and IDC. Therefore, no significant intratumor heterogeneity in the expression of HER-2neu, Bcl-2, and PCNA was observed in IDC. Minor regional variations were observed for EGFR and p53 in IDC. Similarly, no significant regional variation in the expression of markers was observed in DCIS except for PCNA.     

Antarctic reptant decapods: more than a myth?

The impoverished Antarctic decapod fauna is one of the most conspicuous biodiversity phenomena in polar science. Although physiological and ecological approaches have tried to explain the reason for the low decapod biodiversity pattern in the Southern Ocean, the complexity of this problem is still not completely understood. The scant records of crabs south of the Polar Front were always considered as exceptional, and have mostly been ignored by marine biologists world-wide, creating one of the most dogmatic paradigms in polar science. We herein review the record of both adults and larvae of reptants from the Southern Ocean. At present, several species of only lithodid crabs maintain considerable adult populations in circum-Antarctic waters, although they remain absent from the high-Antarctic shelves.     

Larval and osteological development of the mote sculpin (Normanichthys crockeri) (Pisces:Normanichthyidae) from the Independencia Bight, Pisco, Peru

Ontogeny of Normanichthys crockeri is described and illustratedbased on 66 specimens (1.9–20.5 mm; including recentlyhatched larvae through to the transformation stage) collectedin Bahia Independencia, Pisco, Peru. Larvae hatch at approximately1.8 mm, undergo notochord flexion at ca. 6.2–9.0 mm, andtransform to juveniles at ca. 20.0 mm. Larvae were identifiedby the series method, using a combination of meristic and developmentalcharacters that permitted definitive identification. Diagnosticfeatures of the larvae include early development of large, lightlypigmented pectoral fins; early dorsal midline pigment on thetrunk and tail which decreases gradually to none by the beginningof the flexion stage and does not reappear until late postflexionstage; and pigment ventrally, on the midlines of the abdominaland postanal regions, on the preanal until late postflexionstage, at the angular, on the caudal region, and usually atthe cleithrum. Larvae are moderately slender with preanal lengthroughly half of body length (ca. 40–53% body length).They have I,5 pelvic-fin rays, 7+6 principal caudal-fin raysand 36–37 myomeres (11–13+24–26, usually 13+24).The cleithra and bones of the jaws and opercular series areamong the first to begin ossifying. The anterior vertebrae beginto ossify at ca. 5.0 mm and addition is posteriorly. The pectoralfin is the first to begin ray formation, followed sequentiallyby the principal caudal-fin rays, second dorsal- and anal-finrays (forming concurrently), spiny dorsal-fin rays, and pelvic-finrays.     

A multicomponent reaction–diffusion model of a heterogeneously distributed immobilized enzyme

A physical model was derived for the synthesis of the antibiotic cephalexin with an industrial immobilized penicillin G acylase, called Assemblase. In reactions catalyzed by Assemblase, less product and more by-product are formed in comparison with a free-enzyme catalyzed reaction. The model incorporates reaction with a heterogeneous enzyme distribution, electrostatically coupled transport, and pH-dependent dissociation behavior of reactants and is used to obtain insight in the complex interplay between these individual processes leading to the suboptimal conversion. The model was successfully validated with synthesis experiments for conditions ranging from heavily diffusion limited to hardly diffusion limited, including substrate concentrations from 50 to 600 mM, temperatures between 273 and 303 K, and pH values between 6 and 9. During the conversion of the substrates into cephalexin, severe pH gradients inside the biocatalytic particle, which were previously measured by others, were predicted. Physical insight in such intraparticle process dynamics may give important clues for future biocatalyst design. The modular construction of the model may also facilitate its use for other bioconversions with other biocatalysts.     

Evidence that the renin decrease during hypoxia is adenosine mediated in conscious dogs.

This study investigated whether adenosine mediates the decrease in plasma renin activity (PRA) during acute hypoxia. Eight chronically tracheotomized, conscious beagle dogs were kept under standardized environmental conditions and received a low-sodium diet (0.5 mmol.kg body wt(-1).day(-1)). During the experiments, the dogs were breathing spontaneously via a ventilator circuit: first hour, normoxia (21% inspiratory concentration of O(2)); second and third hours, hypoxia (10% inspiratory concentration of O(2)). Each of the eight dogs was studied twice in randomized order in control and theophylline experiments. In theophylline experiments, theophylline, an A(1)-receptor antagonist, was infused intravenously during hypoxia (loading dose: 3 mg/kg within 30 min, maintenance: 0.5 mg. kg(-1). h(-1)). In theophylline experiments, PRA (5.9 +/- 0.8 ng ANG I. ml(-1). h(-1)) and ANG II plasma concentration (15.9 +/- 2.3 pg/ml) did not decrease during hypoxia, whereas plasma aldosterone concentration decreased from 277 +/- 63 to 132 +/- 23 pg/ml (P < 0.05). In control experiments, PRA decreased from 6.8 +/- 0.8 during normoxia to 3.0 +/- 0.5 ng ANG I. ml(-1). h(-1) during hypoxia, ANG II decreased from 13.3 +/- 1.9 to 7.3 +/- 1.9 pg/ml, and plasma aldosterone concentration decreased from 316 +/- 50 to 70 +/- 13 pg/ml (P < 0.05). Thus infusion of the adenosine receptor antagonist theophylline inhibited the suppression of the renin-angiotensin system during acute hypoxia. The decrease in aldosterone occurred independently and is apparently directly related to hypoxia. In conclusion, it is likely that adenosine mediates the decrease in PRA during acute hypoxia in conscious dogs.     

Microscopic anatomy and ultrastructure of the digestive system of three Antarctic shrimps (Crustacea: Decapoda: Caridea)

Mandibles and stomachs of three Antarctic shrimp species (Nematocarcinus lanceopes, Notocrangon antarcticus, and Chorismus antarcticus) were investigated by means of scanning electron microscopy. Transmission electron microscopy of the midgut glands was applied to find out the nutritional status of the animals, which contained a broad variety of food items in their stomachs. In contrast to the Antarctic krill, the three carideans possess a dual filter system; primary filters in the cardia and secondary filters in the pyloric chamber. Morphologically, the mandibles and stomachs of the three species vary considerably; however, their food items are similar. We conclude that stomach contents do not really reflect the different modes of life or habitat preferences of the investigated species.     

Physiological price of an induced chemical defense: photosynthesis, respiration, biosynthesis, and growth

A recurring theme in defense allocation theories is that defenses are costly. Most studies that attempt to quantify a cost of defense seek to establish a trade-off between a component of plant fitness and the level of a constitutive defense. Such estimates are ambiguous because they cannot discount the cost of traits that are correlated with defense but are not themselves defensive. We examined the effects of damage-induced synthesis of furanocoumarins, known defense compounds, on the growth of wild parsnip. Plants that had 2% of their leaf area removed accumulated 8.6% less total biomass and 14% less root biomass than intact plants over a 4-week period. We also found that this small amount of leaf damage significantly reduced net photosynthetic rates 0.5 h after damage; the effect was temporary, as photosynthetic rates were no longer significantly different after 48 h. Lastly, we found that increases in respiration rates associated with damage coincided spatially and temporally with increases in furanocoumarin production, and that respiration increases were phenotypically correlated with furanocoumarin production. When damage-induced changes in furanocoumarin content and respiration rates were expressed in glucose equivalents and compared, the energetic cost of furanocoumarin production (12.6 μg glucose cm⁻²) accounted for all of the increase in respiration (12.0 μg glucose cm⁻²). A comparison of other secondary compounds in damaged and intact leaflets revealed that myristicin, a furanocoumarin synergist, is the only other compound aside from furanocoumarins that is inducible. The inducible defense system of wild parsnip thus appears to involve a small subset of secondary compounds. Synthesis of these compounds is tightly linked to damage-induced rates of respiration. Because the negative impact that damage had on the rate of net photosynthesis was short-lived, the impact of damage on growth observed in this study was likely due to the cost of furanocoumarin synthesis elicited by damage rather than the loss of photosynthetic tissue caused by damage. Received: 4 April 1996 / Accepted: 29 August 1996