Altered regional cardiac wall mechanics are associated with differential cardiomyocyte calcium handling due to nebulette mutations in preclinical inherited dilated cardiomyopathy.

Nebulette (NEBL) is a sarcomeric Z-disk protein involved in mechanosensing and force generation via its interaction with actin and tropomyosin-troponin complex. Genetic abnormalities in NEBL lead to dilated cardiomyopathy (DCM) in humans and animal models. The objectives of this study are to determine the earliest preclinical mechanical changes in the myocardium and define underlying molecular mechanisms by which NEBL mutations lead to cardiac dysfunction. We examined cardiac function in 3-month-old non-transgenic (non-Tg) and transgenic (Tg) mice (WT-Tg, G202R-Tg, A592E-Tg) by cardiac magnetic resonance (CMR) imaging. Contractility and calcium transients were measured in isolated cardiomyocytes. A592E-Tg mice exhibited enhanced in vivo twist and untwisting rate compared to control groups. Ex vivo analysis of A592E-Tg cardiomyocytes showed blunted calcium decay response to isoproterenol. CMR imaging of G202R-Tg mice demonstrated reduced torsion compared to non-Tg and WT-Tg, but conserved twist and untwisting rate after correcting for geometric changes. Ex vivo analysis of G202R-Tg cardiomyocytes showed elevated calcium decay at baseline and a conserved contractile response to isoproterenol stress. Protein analysis showed decreased α-actinin and connexin43, and increased cardiac troponin I phosphorylation at baseline in G202R-Tg, providing a molecular mechanism for enhanced ex vivo calcium decay. Ultrastructurally, G202R-Tg cardiomyocytes exhibited increased I-band and sarcomere length, desmosomal separation, and enlarged t-tubules. A592E-Tg cardiomyocytes also showed abnormal ultrastructural changes and desmin downregulation. This study showed distinct effects of NEBL mutations on sarcomere ultrastructure, cellular contractile function, and calcium homeostasis in preclinical DCM in vivo. We suggest that these abnormalities correlate with detectable myocardial wall motion patterns.

Evaluation of novel genetic algorithm generated schemes for positron emission tomography (PET)/magnetic resonance imaging (MRI) image fusion.

The use and benefits of a multimodality approach in the context of breast cancer imaging are discussed. Fusion techniques that allow multiple images to be viewed simultaneously are discussed. Many of these fusion techniques rely on the use of color tables. A genetic algorithm that generates color tables that have desired properties such as satisfying the order principle, the rows, and columns principle, have perceivable uniformity and have maximum contrast is introduced. The generated 2D color tables can be used for displaying fused datasets. The advantage the proposed method has over other techniques is the ability to consider a much larger set of possible color tables, ensuring that the best one is found. We asked radiologists to perform a set of tasks reading fused PET/MRI breast images obtained using eight different fusion techniques. This preliminary study clearly demonstrates the need and benefit of a joint display by estimating the inaccuracies incurred when using a side-by-side display. The study suggests that the color tables generated by the genetic algorithm are good choices for fusing MR and PET images. It is interesting to note that popular techniques such as the Fire/Gray and techniques based on the HSV color space, which are prevalent in the literature and clinical practice, appear to give poorer performance.

Dietary consistency and the midline sutures in growing pigs.

OBJECTIVES: The purpose of this study was to investigate the effects of reduced masticatory function on midline suture growth and morphology in growing pigs. SETTING AND SAMPLE POPULATION: The sample was 20 pigs separated into two dietary groups and raised at the Department of Anthropology, Harvard University. Midline suture specimens were analyzed at the Department of Orthodontics, University of Washington. MATERIALS AND METHODS: Ten farm pigs and 10 minipigs, all male, were randomly assigned to hard (n = 9) and soft-diet (n = 11) groups. Fluorochromic mineral labels were administered to document bone apposition, and the animals were killed after 12 weeks. Undecalcified sections of the interfrontal, interparietal, internasal, and intermaxillary sutures were evaluated for bone quantity and sutural thickness, interdigitation ratio and growth rate. RESULTS: Soft-diet pigs were characterized by a slower rate of weight gain and less bone than their hard-diet counterparts. Even after correction for weight gain, soft-diet pigs had reduced suture growth rate and thickness. However, no difference in interdigitation ratio was detected between dietary groups. CONCLUSIONS: Restriction to a soft diet reduces midline suture growth and bone apposition in the growing pig.

The end user sensor tree: An end-user friendly sensor database.

Detailed knowledge regarding sensor based technologies for the detection of food contamination often remains concealed within scientific journals or divided between numerous commercial kits which prevents optimal connectivity between companies and end-users. To overcome this barrier The End user Sensor Tree (TEST) has been developed. TEST is a comprehensive, interactive platform including over 900 sensor based methods, retrieved from the scientific literature and commercial market, for aquatic-toxins, mycotoxins, pesticides and microorganism detection. Key analytical parameters are recorded in excel files while a novel classification system is used which provides, tailor-made, experts' feedback using an online decision tree and database introduced here. Additionally, a critical comparison of reviewed sensors is presented alongside a global perspective on research pioneers and commercially available products. The lack of commercial uptake of the academically popular electrochemical and nanomaterial based sensors, as well as multiplexing platforms became very apparent and reasons for this anomaly are discussed.

Colony formation by simian virus 40-transformed human parapharyngeal cells cultured in semisolid agar.

A simian virus 40 (SV40)-transformed line of human parapharyngeal cells (SV-TGo) was cultured in semisolid agar to determine its ability to grow in the absence of an anchoring substratum and to evaluate any phenotypic changes that might have resulted during the isolation of sublines specifically selected for anchorage independence. After 2--3 weeks and 14--15 population doublings in culture, SV-TGo plated with over 1,000% higher efficiency than negative controls (F2408 cells). Sublines, 0.3--2.0 mm in diameter, were isolated and transferred to Leighton tubes in which they underwent an additional 0--7 divisions before senescence after 39--44 total population doublings. Subline phenotype was identical to the original parental phenotype, including epithelioid morphology, organized pattern of growth, extreme sensitivity to density-dependent inhibition of growth, and continuous production of infectious SV40 as detected by the combined tests of cocultivation and direct isolation. Limited division potential was within the range observed for the parental line. The ability to grow in agar without identifiable phenotypic changes was therefore confirmed for this line of SV40-transformed human epithelioid cells.

Sequential histomorphometric analysis of regenerate osteogenesis following mandibular distraction in the rat.

Few studies of distraction osteogenesis in the craniofacial region have examined the dynamic nature of the bone healing process. This study investigated bone formation in distraction sites at various times following slow, moderate, and rapid rates of mandibular distraction in adult rats. After a 3-day latency period, 16 groups of 8-9 rats underwent unilateral mandibular distraction for 5 days at four different rates (0, 0.2, 0.4, and 0.6 mm/day) and were sacrificed at four different time points (6, 10, 24, and 38 days). Vital bone labels were injected prior to sacrifice and histological sections were examined under epifluorescence to measure mineral apposition rate (MAR) and the number of red and green pixels that corresponded to the wavelengths of the two bone labels. These pixel counts were designed to quantify the amount of fluorescent bone formation. For MAR and the pixel counts, no significant differences were found between the distraction rate groups. Over time, MAR was significantly higher (p < 0.001) at 24 days (4.50 microm/day) compared to 38 days (3.78 microm/day). Thus, MAR appears to be elevated at mid-consolidation compared to late consolidation. The pixel counts showed that the 6-day (mid-distraction) and 10-day (early consolidation) time points had significantly lower total fluorescent activity compared to the 24-day (mid-consolidation) and 38-day (late consolidation) time points (p < 0.001). The red, green, and red + green pixel counts were found to correlate significantly but weakly with microdensity (r = 0.318, 0.307, and 0.334, respectively). The pixel counts and microdensity both showed similar patterns over time.

Calcium intake and body weight.

Five clinical studies of calcium intake, designed with a primary skeletal end point, were reevaluated to explore associations between calcium intake and body weight. All subjects were women, clustered in three main age groups: 3rd, 5th, and 8th decades. Total sample size was 780. Four of the studies were observational; two were cross-sectional, in which body mass index was regressed against entry level calcium intake; and two were longitudinal, in which change in weight over time was regressed against calcium intake. One study was a double-blind, placebo-controlled, randomized trial of calcium supplementation, in which change in weight during the course of study was evaluated as a function of treatment status. Significant negative associations between calcium intake and weight were found for all three age groups, and the odds ratio for being overweight (body mass index, >26) was 2.25 for young women in the lower half of the calcium intakes of their respective study groups (P: < 0.02). Relative to placebo, the calcium-treated subjects in the controlled trial exhibited a significant weight loss across nearly 4 yr of observation. Estimates of the relationship indicate that a 1000-mg calcium intake difference is associated with an 8-kg difference in mean body weight and that calcium intake explains approximately 3% of the variance in body weight.

Carbonated beverages and urinary calcium excretion.

BACKGROUND: Intake of carbonated beverages has been associated with increased fracture risk in observational studies. The usual explanation given is that one or more of the beverage constituents increase urinary calcium. OBJECTIVE: We assessed the short-term effects on urinary calcium excretion of carbonated beverages of various compositions. DESIGN: An incomplete random block design was used to study 20-40-y-old women who customarily consumed > or =680 mL carbonated beverages daily. Four carbonated beverages were tested: 2 with caffeine and 2 without. Two contained phosphoric acid as the acidulant and 2 contained citric acid. The study included one neutral control (water) and one positive control (skim or chocolate milk). Serving size was 567 mL for the carbonated beverages and water and 340 mL for the milks. Beverages were consumed with a light breakfast after an overnight fast; no other foods were ingested until urine collection was complete. pH, titratable and total acidity, sodium, creatinine, and calcium were measured in 2-h (morning) fasting and 5-h postbeverage urine specimens. RESULTS: Relative to water, urinary calcium rose significantly only with the milks and the 2 caffeine-containing beverages. The excess calciuria was approximately 0.25 mmol, about the same as previously reported for caffeine alone. Phosphoric acid without caffeine produced no excess calciuria; nor did it augment the calciuria of caffeine. CONCLUSIONS: The excess calciuria associated with consumption of carbonated beverages is confined to caffeinated beverages. Acidulant type has no acute effect. Because the caffeine effect is known to be compensated for by reduced calciuria later in the day, we conclude that the net effect of carbonated beverage constituents on calcium economy is negligible. The skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement.

Bioavailability of the calcium in fortified soy imitation milk, with some observations on method.

BACKGROUND: Calcium-fortified soy milk is growing in popularity, particularly among vegetarians, but the bioavailability of its calcium was not previously known. Additionally, the validity of isotopic labeling methods for fortified liquid products had not been established. OBJECTIVES: The objectives of this study were to compare the bioavailability of the calcium in fortified soy milk with that of calcium in cow milk and to evaluate the method of labeling soy milk for bioavailability testing. DESIGN: A within-subject comparison of extrinsically labeled cow milk with intrinsically and extrinsically labeled soy milks was undertaken in 16 healthy men. In all tests, 300-mg Ca loads were given as a part of a light breakfast after an overnight fast. The milks were physically partitioned into liquid and solid phases to enable evaluation of tracer distribution. RESULTS: Calcium from intrinsically labeled soy milk was absorbed at only 75% the efficiency of calcium from cow milk. Extrinsic labeling of soy milk did not produce uniform tracer distribution throughout the liquid and solid phases and resulted in a 50% overestimate of true absorbability. CONCLUSION: Calcium-fortified soy milk does not constitute a calcium source comparable to cow milk, and extrinsic labeling of such calcium particulate suspensions does not produce the uniform tracer distribution needed for bioavailability testing. Hence, intrinsic labeling of the fortificant is required for such liquid suspensions.

Dietary calcium and vitamin D intake in elderly women: effect on serum parathyroid hormone and vitamin D metabolites.

In this study, the effect of dietary calcium and vitamin D on serum parathyroid hormone and vitamin D metabolites was measured in 376 free-living women aged 65-77 y. Mean calcium intake in both groups was close to the recommended dietary allowance of 800 mg/d. Mean vitamin D intake in the 245 women not taking vitamin D supplements was 3.53 microg/d (141 IU/d), which is below the recommended dietary allowance of 5 microg/d (200 IU/d). To test the hypothesis that vitamin D is more important than calcium in reducing serum parathyroid hormone, the source of dietary calcium intake was subdivided into milk, which is fortified with vitamin D, and nonmilk sources. The serum parathyroid hormone concentration was inversely correlated with calcium intake derived from milk (r = -0.20, P < 0.01) but not from nonmilk sources (r = -0.06). Furthermore, serum calcidiol correlated with milk calcium intake (r = 0.35, P < 0.001) but not with nonmilk calcium intake (r = 0.10). Multivariate analysis showed a significant effect of season on serum calcidiol but not on serum parathyroid hormone. Serum parathyroid hormone was inversely correlated with serum calcidiol (r = -0.33, P < 0.001) and the regression predicted that mean serum parathyroid hormone would be reduced in the elderly to concentrations considered normal in the young when serum calcidiol is 122 nmol/L (49 ng/mL); this would require a much higher recommended dietary allowance for vitamin D than 5 microg/d (200 IU/d).

Serum vitamin D metabolites and calcium absorption in normal young and elderly free-living women and in women living in nursing homes.

Vitamin D deficiency, which causes osteomalacia, may also be important in the pathogenesis of age-related osteoporosis. We studied serum vitamin D metabolites in 52 young women (mean age: 30 +/- 3 y; range: 25-35 y), 64 elderly free-living women (mean age: 71 +/- 4 y; range: 65-82 y), and 60 elderly women living in nursing homes (mean age: 84 +/- 9 y; range: 61-102 y). Mean serum 25-hydroxyvitamin D (calcidiol) was 10.8 +/- 4.4 nmol/L (27 +/- 11 ng/mL) in women living in nursing homes and was similar to that of free-living young (11.3 +/- 4.2 nmol/L, or 28 +/- 10 ng/mL) and elderly (11.5 +/- 3.2 nmol/L, or 29 +/- 8 ng/mL) women. Vitamin D deficiency (defined as serum calcidiol < 4.8 nmol/L, or 12 ng/mL) occurred in 8% of women living in nursing homes, in 6% of the young women, and in 1.6% of the free-living elderly women. Serum calcidiol was significantly correlated with vitamin D intake (r = 0.25, P < 0.05) and inversely correlated with serum intact parathyroid hormone (iPTH) (r = -0.16, P < 0.03). Serum iPTH increased with age and secondary hyperparathyroidism was observed in 17% of the women living in nursing homes. Calcium absorption declined with age, but calcium absorption and serum 1 alpha,25-dihydroxyvitamin D (calcitriol) were significantly lower in women living in nursing homes, which probably contributed to the secondary hyperparathyroidism. In conclusion, normal serum calcidiol may avoid the problem of osteomalacia, but it does not correct malabsorption of calcium. Although calcitriol corrects the malabsorption of calcium, it remains to be seen whether higher amounts of vitamin D can normalize the calcium malabsorption of aging.

Craniofacial sutures: morphology, growth, and in vivo masticatory strains.

The growth and morphology of craniofacial sutures are thought to reflect their functional environment. However, little is known about in vivo sutural mechanics. The present study investigates the strains experienced by the internasal, nasofrontal, and anterior interfrontal sutures during masticatory activity in 4-6-month-old miniature swine (Sus scrofa). Measurements of the bony/fibrous arrangements and growth rates of these sutures were then examined in the context of their mechanical environment. Large tensile strains were measured in the interfrontal suture (1,036 microepsilon +/- 400 SD), whereas the posterior internasal suture was under moderate compression (-440 microepsilon +/- 238) and the nasofrontal suture experienced large compression (-1,583 microepsilon +/- 506). Sutural interdigitation was associated with compressive strain. The collagen fibers of the internasal and interfrontal sutures were clearly arranged to resist compression and tension, respectively, whereas those of the nasofrontal suture could not be readily characterized as either compression or tension resisting. The average linear rate of growth over a 1-week period at the nasofrontal suture (133.8 micrometer, +/- 50.9 S.D) was significantly greater than that of both the internasal and interfrontal sutures (39.2 micrometer +/- 11.4 and 65. 5 micrometer +/- 14.0, respectively). Histological observations suggest that the nasofrontal suture contains chondroid tissue, which may explain the unexpected combination of high compressive loading and rapid growth in this suture.

Comparative response to UV irradiation of cytoskeletal elements in rabbit and skate lens epithelial cells.

PURPOSE: This work reports a differential effect of ultraviolet A (UVA) irradiation on the three major cytoskeletal structures, actin and vimentin filaments and microtubules of lens cells in primary culture. The effect on cells from lens of the skate (a bottom-dwelling marine elasmobranch) was compared with that on rabbit lens, in order to assess UVA sensitivity as a function of exposure to these wavelengths in the native habitat. METHODS: Exposure intervals of irradiation time up to 6 hours were selected, at fluences from 13.5 to 54.4 J/cm2 and at 365 +/- 45 nm wavelength, to represent mild to moderate physiological levels. Cultures were fixed and processed with anti-alpha-tubulin-FITC and rhodamine phalloidin, or with anti-vimentin FITC and rhodamine phalloidin conjugates. RESULTS: With epifluorescence microscopy, it was found that microtubules were most sensitive to UVA irradiation (in depolymerizing), followed by actin, with vimentin hardly at all affected. Irradiation for 6 hours followed by incubation for 3 days in fresh medium showed no recovery of actin but good recovery of microtubule organizing centers, followed by mitosis in many (rabbit) cells. Skate cells were more sensitive and showed no recovery. CONCLUSIONS: In view of the role of cytoskeletal elements in intracellular structure, cell division and transport, their disruption supports the hypothesis that UVA may damage lens epithelial cells in vivo so as to contribute to cataract formation. In addition, the data suggest that the lenses of animals exposed to sunlight require effective cytoskeletal repair mechanisms to avoid loss of function.

Herpes viruses and cancer.

PIP: Type 2 herpes simplex virus belongs to the herpes virus group, members of which have been shown to cause cancer in animals -- kidney cancer in frogs, lymphoid cancer in chickens and rabbits, and lung cancer in sheep. A herpes virus causes Burkett's lymphoma in humans; another causes nasopharyngeal cancer in humans. Herpes simplex viruses are common in humans in cervical and vaginal sores in women and in the genital tract in men (an estimated 15% of men older than 15). It is transmitted venereally. Type 2 herpes simplex virus has been epidemiologically associated with cervical cancer. It has been found in prostate cancer cells. In a hybridization experiment with DNA from cervical cancer cells, DNA from type 2 herpes simplex virus was found, but 60% of the viral DNA molecule was missing. In the chicken lymphoid cancer caused by a herpes virus, live virus vaccine eradicated the disease. This suggests that, if type 2 herpes simplex virus is found to cause cervical cancer, a vaccination cure can be developed.^ieng

Intra-aortic balloon pump issues from a management perspective.

This article summarizes the successful development and implementation of an IABP program. Administrative, fiscal, and educational considerations are described. It is important for nursing leaders to maintain a patient focus in an environment that currently reacts to both internal and external pressures.

Ethical considerations in drug administration for critically ill patients.

The ethical dilemmas critical care nurses face in daily practice are increasing as treatments are weighed against the benefit in individual patients. Managing critically ill patients holistically creates ethical challenges on a daily basis. Determining how to assist patients and significant others in making sound ethical decisions is critical to optimal outcomes. Case studies are presented to illustrate further how cost effectiveness will continue to have a major role in determining patient care in the 21st century.

Sex steroid hormone determination of the maternal brain: effects beyond reproduction.

Herein we discuss the effects of hormones on reproduction, but with a focus on the ripples that emanate from the main effects. That is, the role of hormones in reproductive events is both well-known and well accepted; less studied and understood are effects that appear to be ancillary to the primary objectives of the hormonal effects, which support, complement and extend their primary effects. We present evidence for how the hormonal stimulation of pregnancy constructs the maternal brain; makes it more efficient; enhances cognition; regulates stress responsiveness; modifies sensory systems (we discuss mainly olfaction); neurogenesis; and learning. Thus, steroid and other hormones and neuropeptides restructure the nervous system, particularly of females, to produce and regulate maternal behavior as well as behaviors and physiological systems that contribute to and support what is arguably the primary function of the hormones: survival and effective nurturance of the female's metabolic and genetic investment.

Chronic dietary fiber supplementation with wheat dextrin does not inhibit calcium and magnesium absorption in premenopausal and postmenopausal women.

This placebo-controlled, randomized, crossover clinical study examined the effect of chronic wheat dextrin intake on calcium and magnesium absorption. Forty premenopausal and post menopausal women (mean ± SD age 49.9 ± 9.8 years) consumed wheat dextrin or placebo (15 g/day) for 2 weeks prior to (45)calcium ((45)Ca) and (26)magnesium ((26)Mg) absorption testing. After a standardized breakfast, serial blood and urine samples were obtained. The mean ± SD area under the curve from 0 to 9 h for (45)Ca specific activity was 0.81 ± 0.21 for wheat dextrin and 0.82 ± 0.22 for placebo, showing that wheat dextrin had no effect on calcium absorption. The mean ± SD percentage excess of (26)Mg/(24)Mg was 7.8% ± 2.1% for wheat dextrin and 7.9% ± 2.6% for placebo, showing that wheat dextrin had no effect on magnesium absorption. In conclusion, chronic wheat dextrin consumption did not inhibit calcium or magnesium absorption from the gastrointestinal tract in women.

The effects of tooth extraction on alveolar bone biomechanics in the miniature pig, Sus scrofa.

OBJECTIVE: This study investigated the role of occlusion in the development of biomechanical properties of alveolar bone in the miniature pig, Sus scrofa. The hypothesis tested was that the tissues supporting an occluding tooth would show greater stiffness and less strain than that of a non-occluding tooth. DESIGN: Maxillary teeth opposing the erupting lower first molar (M(1)) were extracted on one side. Occlusion developed on the contralateral side. Serially administered fluorochrome labels tracked bone mineralisation apposition rate (MAR). A terminal experiment measured in vivo buccal alveolar bone strain on occluding and non-occluding sides during mastication. Ex vivo alveolar strains during occlusal loading were subsequently measured using a materials testing machine (MTS/Sintech). Whole specimen stiffness and principal strains were calculated. RESULTS: MAR tended to be higher on the extraction side during occlusion. In vivo buccal shear strains were higher in the alveolar bone of the occluding side vs. the extraction side (mean of 471 microvarepsilon vs. 281 microvarepsilon, respectively; p=0.04); however, ex vivo shear strains showed no significant differences between sides. Stiffness differed between extraction and occlusion side specimens, significantly so in the low load range (344 vs. 668 MPa, respectively; p=0.04). CONCLUSIONS: Greater in vivo shear strains may indicate more forceful chews on the occluding side, whereas the similarity in ex vivo bone strain magnitude suggests a similarity in alveolar bone structure and occlusal load transmission regardless of occlusal status. The big overall change in specimen stiffness that was observed was likely attributable to differences in the periodontal ligament rather than alveolar bone.