Evaluation of Heavy Metals in Vegetables from Two Origins Marketed in Northern Peru

The objective of the study was to evaluate the concentration of arsenic, chromium, cadmium, and lead in onion (Allium fistulosum and Allium cepa), tomato (Solanum lycopersicum), and celery (Apium graveolens) from two origins (local - Chachapoyas province and from the coast-province of Chiclayo) that are sold in the model market of the city of Chachapoyas. Six samples were taken on three different dates in November 2020, which were collected by non-probabilistic sampling (by convenience), which allowed choosing the most appropriate sample (according to its origin). For the determination of heavy metals, the Agilent 4100 MP-AES spectrometer was used. The concentration of As, Cr, and Cd in the vegetables remained below the Maximum Allowable Limits of the international standards with which they were compared; however, the concentration of Pb exceeded the Maximum Allowable Limits in all the samples analyzed, obtaining the lowest value in the celery samples from the local origin (0.15 mg.kg-1) and the highest value in the tomato samples from the coast (0.21 mg.kg-1). Therefore, it is concluded that only Pb is higher than the Maximum Allowable Limits with which it was compared.

Associations of Serum Levels of Sex Hormones in Follicular and Luteal Phases of the Menstrual Cycle with Breast Tissue Characteristics in Young Women

Background

In previous work in young women aged 15–30 years we measured breast water and fat using MR and obtained blood for hormone assays on the same day in the follicular phase of the menstrual cycle. Only serum growth hormone levels and sex hormone binding globulin (SHBG) were significantly associated with percent breast water after adjustment for covariates. The sex hormones estradiol, progesterone and testosterone were not associated with percent water in the breast in the follicular phase of the menstrual cycle. In the present study we have examined the association of percent breast water with serum levels of sex hormones in both follicular and luteal phase of the menstrual cycle.

Methods

In 315 healthy white Caucasian young women aged 15–30 with regular menstrual cycles who had not used oral contraceptives or other hormones in the previous 6 months, we used MR to determine percent breast water, and obtained blood samples for hormone assays within 10 days of the onset of the most recent menstrual cycle (follicular phase) of the cycle on the same day as the MR scan, and a second blood sample on days 19–24 of the cycle. Serum progesterone levels of > = 5 mmol/L in days 19–24 were used to define the 225 subjects with ovulatory menstrual cycles, whose data are the subject of the analyses shown here.

Results

SHBG was positively associated with percent water in both follicular and luteal phases of the menstrual cycle. Total and free estradiol and total and free testosterone were not associated with percent water in the follicular phase, but in young women with ovulatory cycles, were all negatively associated with percent water in the luteal phase.

Conclusions

Our results from young women aged 15–30 years add to the evidence that the extent of fibroglandular tissue in the breast that is reflected in both mammographic density and breast water is associated positively with higher serum levels of SHBG, but not with higher levels of sex hormones.

Bilateral symmetry of breast tissue composition by magnetic resonance in young women and adults

BACKGROUND

Some reports suggest that there is a slightly higher frequency of breast cancer in the left breast compared with the right in middle-aged women. The reasons for this association are unknown. The water and fat content of both breasts was compared using magnetic resonance (MR). Breast water by MR reflects fibro-glandular tissue and is strongly positively correlated with percent mammographic density, a strong risk factor for breast cancer.

METHODS

Magnetic resonance was used to measure fat and water content of the breast in 400 young women aged 15-30 years and a random sample of 100 of their mothers. All MR examinations were carried out using a 1.5T MR system, and 45 contiguous slices were obtained in the sagittal plane. One reader identified the breast tissue in the image, and subsequently, fat and water content was calculated using a three-point Dixon technique. Left- and right-sided images were read independently in random order.

RESULTS

In young women, mean percent water was on average 0.84 % higher in the right compared with the left breast (p < 0.001) and total breast water was on average 6.42 cm(3) greater on the right side (p < 0.001). In mothers, there were no significant differences in any breast measure between right and left sides.

CONCLUSION

The small differences in breast tissue composition in young women are unlikely to be associated with large differences in breast cancer risk between sides. The reported excess of left-sided breast cancer in older women is unlikely to be explained by differences in breast tissue composition.

Syntheses, thermal reactivities, and computational studies of aryl-fused quinoxalenediynes: effect of extended benzannelation on Bergman cyclization energetics

A series of [b]-fused 6,7-diethynylquinoxaline derivatives have been synthesized through an imine condensation strategy to examine the effect of extended benzannelation on the thermal reactivity of enediynes. Absorption and emission spectra of the highly conjugated quinoxalenediynes were red-shifted approximately 100-200 nm relative to those of 1,2-diethynylbenzene. Strong exotherms indicative of enediyne cyclization were observed by differential scanning calorimetry, while solution cyclizations in the presence of 1,4-cyclohexadiene confirmed C(1)-C(6) Bergman cyclization. To provide further insight into Bergman cyclization energetics, computational studies were performed to compare changes in the cyclization enthalpy barrier, reaction enthalpy, and barrier of retro-Bergman ring-opening. Extension of benzannelation from 1,2-diethynylbenzene to either 2,3-diethynylnaphthalene or the 6,7-diethynylquinoxalines had a minimal effect on the cyclization barrier. In comparison, the enthalpies of cyclization were increased upon linearly extended benzannelation, which resulted in reduced barriers to retro-Bergman ring-opening. In addition, the orientation of extended benzannelation was found to have a significant effect on the cyclization endothermicity. In particular, 5,6-diethynylquinoxaline exhibited a 6.9 kcal/mol decrease in cyclization enthalpy compared to 6,7-diethynylquinoxaline due to increased aromatic stabilization energy in the respective angularly versus linearly fused azaacene cyclized products.

Robust correction of spike noise: application to diffusion tensor imaging

Echo-planar imaging (EPI) -based diffusion tensor imaging (DTI) is particularly prone to spike noise. However, existing spike noise correction methods are impractical for corrupted DTI data because the methods correct the complex MRI signal, which is not usually stored on clinical MRI systems. The present work describes a novel Outlier Detection De-spiking technique (ODD) that consists of three steps: detection, localization, and correction. Using automated outlier detection schemes, ODD exploits the data redundancy available in DTI data sets that are acquired with a minimum of six different diffusion-weighted images (DWIs) with similar signal and noise properties. A mathematical formulation, describing the effects of spike noise on magnitude images, yields appropriate measures for an outlier detection scheme used for spike detection while a normalization-dependent outlier detection scheme is used for spike localization. ODD performs accurately on diverse DTI data sets corrupted by spike noise and can be used for automated control of DTI data quality. ODD can also be extended to other MRI applications with data redundancy, such as dynamic imaging and functional MRI.

Abstract CN13-02: Breast tissue composition and risk of breast cancer

CN13-02

Background

Susceptibility to breast carcinogens is greatest before the age of 20 years. We have used magnetic resonance (MR) to measure the water content of the breast in young women, and have identified factors associated with variations in breast water. Breast water, like mammographic density, reflects fibro-glandular breast tissue, which is strongly associated with breast cancer risk in middle aged and older women.

Methods

We recruited 400 young women aged 15-30 years and their mothers, measured breast water and fat in daughters using (MR), and obtained anthropometric and other data. Mothers provided mammograms (n=365) and a random sample (n=100) also had breast MR.

Results

Percent water by MR in daughters (median=44.8%) was greater than in mothers (median=27.8%) (P&lt;0.0001), and was greater in daughters aged 15-19 years (n=199; median=49%) than in those aged 20-30 years (n=201; median=41%). Percent water in daughters was correlated with both breast water (n=100 pairs; r=0.28; p=0.005), and percent mammographic density in mothers (n=356 pairs; r=0.25, p&lt;0.0001). Percent water in daughters was independently associated with their age (p=0.04) and weight (p&lt;0.0001) (both inversely), and with their height (p&lt;0.0001) and percent density in their mothers’ mammogram (p&lt;0.0001) (both positively).

Conclusions

Percent breast water was greatest at ages when susceptibility to breast carcinogens is also greatest. The distribution of breast water according to age was consistent with a model in which mammographic density in mid-life is in part the result of genetic influences and growth and development in early life that determine initial breast tissue composition.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):CN13-02.

A fast implementation of the minimum spanning tree method for phase unwrapping

A new implementation of the minimum spanning tree (MST) phase unwrapping method is presented. The time complexity of the MST method is reduced from O(n2) to O(n log2 n), where n is the number of pixels in the phase map. Typical 256 x 256 phase maps from magnetic resonance imaging can be unwrapped in seconds, compared with tens of minutes with the O(n2) implementation. This makes the pixel-level MST method time efficient and practically attractive. Index Terms-Image processing, magnetic resonance imaging, medical imaging, phase unwrapping.

Information systems disaster planning in the patient care environment

This article focuses on preparedness planning for the nurse manager in the event of a network failure of a hospital clinical information system. The evolution of health care information systems is discussed. A 4-step preparation model is discussed to aid the nurse manager in preparing for network failure.

Laser in situ Keratomileusis for Simple Myopic, Mixed, and Simple Hyperopic Astigmatism

PURPOSE

To summarize initial results of astigmatic laser in situ keratomileusis (LASIK) for 41 eyes of 26 patients using the EC-5000 Nidek system and assess its safety, efficacy and predictability.

METHODS

The EC-5000 Nidek excimer laser was used to correct simple myopic, mixed, and simple hyperopic astigmatism with manifest cylinder from 2.00 to 6.50 D. Ablation zone diameters were 6.5 mm (steep meridian ablation) to 7.5 mm (flat meridian ablation) with a repetition rate of 40-41 Hz. In eyes with simple myopic and mixed astigmatism, ablation was performed in both meridians; in eyes with simple hyperopic astigmatism, ablation was performed in the flat meridian alone. Follow-up was 3 months in all eyes.

RESULTS

Uncorrected visual acuity was 20/40 or better in 85% of the eyes. Uncorrected visual acuity was equal to the preoperative spectacle-corrected visual acuity in 63% of the eyes. Intended cylinder correction was within 1.00 D in 95% of eyes. No eyes lost lines of spectacle-corrected visual acuity.

CONCLUSION

LASIK using the EC-5000 excimer laser appears to effective in the treatment of simple myopic, mixed, and simple hyperopic astigmatism, with favorable results as compared to those previously described for astigmatic keratotomy.

Interview with a perioperative burn nurse

This is an interview with a staff nurse who is presently working in the operating room (OR) with burn patients. Special knowledge and techniques specific to the OR are discussed. Personal thought on possible research and the future role of perioperative nurses in caring for the burn patient are also addressed.

Hyperopic Shift and Myopic Regression in a Patient 7 Years After Bilateral Refractive Keratotomy

PURPOSE/METHODS

To report a patient who developed hyperopic progression in one eye and myopic regression in the other eye following bilateral, non-simultaneous refractive keratotomy.

RESULTS

Uncorrected visual acuity improved to 20/25 and 20/25-2 in the right and left eyes, respectively, 3 months following refractive keratotomy (one procedure in the right eye, two procedures in the left eye). The visual acuity was not stable over time and almost 8 years after surgery, uncorrected distance visual acuity was 20/40- and 20/200. The spherical equivalent refraction of the right eye progressed from -0.50 diopter (D) 3 months after surgery to +1.25 D several years later. The left eye regressed from a spherical equivalent refraction of -0.75 D 3 months after the second surgery to -2.50 D more than 7 years postoperatively. Slit-lamp microscopy disclosed deeper, opaque incisions in the hyperopic eye, and shallower and more transparent incisions in the myopic eye.

CONCLUSIONS

The shift toward hyperopia and myopia in an individual suggest that instability of the radial keratotomy wound may be related to local wound healing events that are, in part, related to incision depth.

Interaction of steroid hormone receptors with transcription factors involves chromatin remodelling

The mechanism by which steroid hormones modulate promoter utilization is not clear. Evidence from transfection studies and cell-free assays points to an interaction of the hormone receptors with general transcription factors, as well as with sequence-specific transcription factors. Moreover co-activators or transcription intermediary factors, have been identified which could mediate some of the transcriptional effects of the hormone-receptor complex. However, in addition to this interaction of receptors with proteins directly involved in transcription, a participation of chromatin structure in gene regulation by steroid hormones is becoming increasingly evident. In the case of the MMTV promoter, the nucleosomal organization seems to be responsible for transcriptional repression prior to hormonal stimulation. This effect is due to occlusion by a nucleosome positioned on the MMTV promoter sequences in such a way that essential transcription factors cannot access their recognition sites. Following hormone induction, a remodelling of the nucleosome structure takes place which enables a whole complement of sequence specific transcription factors to assemble on the promoter. Since a complete occupancy of binding sites does not take place when the promoter is present as naked DNA, the nucleosomal organization appears to be required for the proper synergism between transcription factors following hormonal induction. According to this model, the positioning of a nucleosome sets the stage for constitutive repression and hormone induction of the MMTV promoter.

Analysis of astigmatic keratotomy with a 5.0-mm optical clear zone

PURPOSE

To investigate the surgically induced refractive change after astigmatic keratotomy with a 5.0-mm optical clear zone in patients with severe naturally occurring astigmatism.

METHODS

We analyzed surgically induced refractive change in 40 consecutive eyes undergoing astigmatic keratotomy with a 5.0-mm optical clear zone. The surgically induced refractive change was calculated according to the method of Holladay, Cravy, and Koch with some modifications. Eyes were divided into two groups: Group I included eyes with mixed astigmatism and a maximum preoperative spherical equivalent of +1.25 diopters that underwent arcuate keratotomy, and Group II included eyes with compound myopic or simple myopic astigmatism (maximum preoperative spherical equivalent of -3.00 diopters) or mixed astigmatism with low minus spherical equivalent that underwent four-incision radial keratotomy and arcuate keratotomy.

RESULTS

After refractive surgery, all eyes experienced a reduction of astigmatism when examined three months or more after surgery. Only one eye from each group was overcorrected. The magnitude of refractive astigmatism of surgically induced refractive change was 3.25 +/- 0.90 diopters for eyes in Group I and 3.25 +/- 0.80 diopters for eyes in Group II. There was minimal axis deviation. Eyes in Group I had more flattening with the wound than steepening against the wound, with a coupling ratio of -0.86 +/- 0.36, whereas in Group II, there was flattening both with the wound and against the wound. The net effect of surgery (sum of the primary and secondary effects) was more flattening than steepening in Group I eyes, and flattening of the circumference of the eye in Group II. A decrease of one line of best-corrected visual acuity was observed in one (6.6%) of 15 eyes in Group I and in two (8%) of 25 eyes in Group II.

CONCLUSIONS

A 5.0-mm optical clear zone arcuate keratotomy is an effective method for correcting moderate to severe naturally occurring astigmatism. Further investigation of this optical clear zone size on glare and contrast sensitivity testing is necessary and is underway.

Light-regulated promoters from Synechocystis PCC6803 share a consensus motif involved in photoregulation

A library of Synechocystis PCC6803 (S.6803) DNA cloned in front of the promoterless cat reporter gene of the plasmid pFF11 was used to transform S.6803 to high light-dependent resistance to chloramphenicol. In five clones harbouring a stably replicating pFF11-derived plasmid, this phenotype occurred independently of the photosystem II electron transport and resulted from the correlated increase of CAT activity level and cat mRNA accumulation. The five promoter inserts contained no Escherichia coli sigma 70 promoter element, in agreement with their lack of activity in this organism, but shared two conserved motifs. Two secondary mutations, which restored light-regulated promoter activity to an inactive mutant of the smallest insert, mapped within one of the common motifs, emphasizing the probable involvement of this element in photoregulation.

Influences of renal nerves and pregnancy on renin secretion in sheep

To investigate the role of the renal nerves in the control of renin secretion during pregnancy, we prepared sheep with one denervated kidney, bilateral renal vein catheters, and an inflatable aortic occluder. The renin secretory responses to step reductions of renal perfusion pressure (RPP) of the innervated and denervated kidneys were compared in eight nonpregnant and nine pregnant (115-130 days gestation) sheep in a normal conscious state. Nonpregnant sheep had average basal levels of mean arterial pressure (MAP) of 91 +/- 3 mmHg, plasma renin activities (PRA) of 2.3 +/- 0.4 ng ANG I.ml-1.3 h-1, and plasma angiotensin (ANG) concentrations of 8.4 +/- 1.1 pg/ml. Pregnant sheep had reduced levels (P < 0.01) of MAP (76 +/- 3 mmHg) but elevated levels of PRA (3.8 +/- 0.4 ng ANG I.ml-1.h 3-1; P < 0.5) and ANG II (12.0 +/- 1.6 pg/ml; P = 0.08). Four successively reduced levels of RPP were observed for 15 min each in both groups of sheep. In both groups, RPP was reduced to a final level of 51 +/- 2 mmHg. The renal venous-arterial difference of PRA (v-aPRA) from the innervated kidneys was increased as RPP was reduced. However, there was little response of v-aPRA to RPP in denervated kidneys. In nonpregnant sheep, the relationship between RPP and renin secretion rate was characterized by an initially slow phase, over which small reductions of RPP resulted in small increases in renin secretion. As RPP fell, this relationship became progressively steeper in nonpregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)