Minimagnetospheres above the lunar surface and the formation of lunar swirls.

In this paper we present in situ satellite data, theory, and laboratory validation that show how small-scale collisionless shocks and minimagnetospheres can form on the electron inertial scale length. The resulting retardation and deflection of the solar wind ions could be responsible for the unusual "lunar swirl" patterns seen on the surface of the Moon.

Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) in iron foundry workers.

Diisocyanates are a group of chemically reactive agents, which are used in the production of coatings, adhesives, polyurethane foams, and parts for the automotive industry and as curing agents for cores in the foundry industry. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) is associated with respiratory sensitization and occupational asthma. However, limited research has been performed on the quantitative evaluation of dermal and inhalation exposure to MDI in occupationally exposed workers. The objective of this research was to quantify dermal and inhalation exposure levels in iron foundry workers. Workers involved in mechanized moulding and mechanized production of cores were monitored: 12 core makers, 2 core-sand preparers, and 5 core installers. Personal breathing-zone levels of MDI were measured using impregnated filter sampling. Dermal exposure to MDI was measured using a tape-strip technique. Three or five consecutive tape-strip samples were collected from five exposed skin areas (right and left forefingers, left and right wrists, and forehead). The average personal air concentration was 0.55 microg m(-3), 50-fold lower than the Swedish occupational exposure limit of 30 microg m(-3). The core makers had an average exposure of 0.77 microg m(-3), which was not significantly different from core installers' and core-sand preparers' average exposure of 0.16 microg m(-3) (P = 0.059). Three core makers had a 10-fold higher inhalation exposure than the other core makers. The core makers' mean dermal exposure at different skin sites varied from 0.13 to 0.34 microg while the two other groups' exposure ranged from 0.006 to 0.062 microg. No significant difference was observed in the MDI levels between the skin sites in a pairwise comparison, except for left forefinger compared to left and right wrist (P < 0.05). In addition, quantifiable but decreasing levels of MDI were observed in the consecutive tape strip per site indicating MDI penetration into the skin. This study indicates that exposure to MDI can be quantified on workers' skin even if air levels are close to unquantifiable. Thus, the potential for uncured MDI to deposit on and penetrate into the skin is demonstrated. Therefore, dermal exposure along with inhalation exposure to MDI should be measured in the occupational settings where MDI is present in order to shed light on their roles in the development of occupational isocyanate asthma.

Linell classification of breast cancer morphology compared to histologic grading, S-phase fraction and DNA-ploidy.

One hundred and fifty-eight histologically verified mammary carcinomas with known mammographic doubling time (DT) were studied with special emphasis on a morphologic classification proposed by Linell et al. [8, 12, 14, 15]. The hypothesis that Linell classification of ductal carcinomas into comedo, tubuloductal and tubular carcinomas is easy to perform with small inter-observer variations, was not fully confirmed. The Linell classification was found to correlate well with conventional WHO malignancy grading, S-phase fraction and DNA-ploidy. The Linell classification also correlated to surgical stage, lymph node status and DT, but not at all to tumour size. Using distant disease-free survival as an endpoint, the Linell classification gave prognostic information comparable to conventional histologic grading, seeming to be a simple, cheap and reliable method well worth trying on a larger scale.

Breast carcinoma growth rate described by mammographic doubling time and S-phase fraction. Correlations to clinical and histopathologic factors in a screened population.

BACKGROUND: In a retrospective study, correlations among mammographic doubling times (DT), clinicopathologic prognostic factors, and cytometric predictors were examined. METHODS: One hundred fifty-eight patients with the possibility to calculate mammographic tumor DT were selected and the tumors were histologically reexamined and flow cytometric analysis for ploidy and S-phase fraction (SPF) was performed. RESULTS: The tumors were Stage I in 68%, and 45% were detected by mammographic screening. DT ranged from 0.6 months to an indefinite time (median, 9.0 months). Short DT was significantly correlated to large tumor size (P = 0.01) and advanced pathologic tumor stage (P = 0.016), but there was no correlation between DT and histologic grade. Ploidy analysis indicated that there were 57% aneuploid and 7% tetraploid tumors. There was a significant overrepresentation of euploid tumors among tumors smaller than 10 mm (P = 0.02). Ploidy was correlated to histologic grade (P less than 0.001) and DT (P = 0.009). SPF was calculated in 122 cases. SPF correlated significantly with pathologic stage (P = 0.002), tumor size (P = 0.037), histologic grade (P = 0.001), the presence of axillary lymph node metastases (P = 0.046), DT (P = 0.02), and DNA ploidy (P less than 0.001). Compared with interval carcinoma, screening-detected carcinoma showed favorable characteristics concerning size, stage, DT, ploidy, and SPF but not regarding histologic grade and axillary lymph node metastases. CONCLUSIONS: DT shows great variations. Factors related to tumor biology (i.e., DT, DNA ploidy, and SPF) are strongly correlated with one another, but they have no correlation with axillary lymph node metastases. Cancer detected by screening is discovered at an early stage and shows favorable characteristics concerning DT, ploidy, and SPF.

Mammographic growth rate, DNA ploidy, and S-phase fraction analysis in breast carcinoma. A prognostic evaluation in a screened population.

BACKGROUND: The authors examined prognostic factors in 158 cases of breast carcinoma with known mammographic tumor volume doubling times (DT). METHODS: The tumors were retrospectively reexamined histologically and flow cytometric analysis of DNA ploidy and S-phase fraction (SPF) was performed on archival paraffin-embedded material in each case. Life tables and Cox multivariate analyses were used for statistical evaluation of prognostic factors. RESULTS: In univariate analysis of survival data, clinical and pathologic stage, histologic grade, the presence of axillary lymph node metastases, and SPF were significant prognostic predictors, but mammographic DT and DNA ploidy were not. SPF also contributed prognostic information in the subgroup of carcinoma cases detected by screening. In a Cox multivariate analysis, SPF, the presence of axillary lymph node metastases, and Stage II-III disease (as opposed to Stage I disease) were independent significant predictors of survival. In univariate analyses of distant disease-free survival, clinical and pathologic stage, tumor size, histologic grade, the presence of involved axillary nodes, DT, and SPF all were significant prognostic factors. CONCLUSIONS: SPF, stage, and lymph node status were important prognostic factors in this patient material with predominantly small and node-negative breast carcinomas, whereas DNA ploidy and mammographic DT provided less prognostic information. The prognosis of carcinoma detected during screening did not differ significantly from that of breast carcinoma discovered otherwise in this selected patient group.

Regulation of Nitrate Uptake in Penicillium chrysogenum by Ammonium Ion.

A nitrate uptake system is induced (along with nitrate reductase) when NH(4) (+)-grown Penicillium chrysogenum is incubated with inorganic nitrate in synthetic medium in the absence of NH(4) (+). Nitrate uptake and nitrate reduction are probably in steady state in fully induced mycelium, but the ratios of the two activities are not constant during the induction period. Substrate concentrations of ammonium cause a rapid decay of nitrate uptake and nitrate reductase activity. The two activities are differentially inactivated (the uptake activity being more sensitive). Glutamine and asparagine are as effective as NH(4) (+) in suppressing nitrate uptake activity. Glutamate and alanine were about half as effective as NH(4) (+). Cycloheximide interferes with the NH(4) (+)-induced decay of nitrate uptake activity. The ammonium transport system is almost maximally deinhibited (or derepressed) in nitrate-grown mycelium.

Effect of cycloheximide on L-leucine transport by Penicillium chrysogenum: involvement of calcium.

Cycloheximide (actidione) has an immediate inhibitory effect on amino acid transport by nitrogen-starved or carbon-starved mycelium suspended in phosphate buffer. High concentrations of phosphate alone are slightly inhibitory; cycloheximide appears to potentiate the effect of phosphate. Ca(2+) reverses the inhibition of transport caused by phosphate plus cycloheximide. Ca(2+) did not relieve the inhibition of protein synthesis. Cycloheximide promotes a continual uptake of (45)Ca(2+) by the mycelium. The cumulative results suggest that (i) membrane-bound Ca(2+) is involved in amino acid transport, (ii) cycloheximide labilizes the membrane-bound Ca(2+), and (iii) phosphate forms a complex with Ca(2+) making it unavailable for its role in transport. The effect of cycloheximide described above is observed within 1 to 2 min after addition of the antibiotic. This initial inhibition occurs more rapidly with 10(-3) M cycloheximide than with 10(-5) M cycloheximide. However, after a longer preincubation time, a curious inverse relationship between cycloheximide concentration and amino acid transport is observed. The mycelium incubated with 10(-5) M cycloheximide remains strongly inhibited (unless the antibiotic is washed away). The mycelium incubated with 10(-3) M cycloheximide recovers about 40% of the transport activity lost during the rapid initial phase. We have no obvious explanation for the inverse effect.