Reactivating head regrowth in a regeneration-deficient planarian species.

Species capable of regenerating lost body parts occur throughout the animal kingdom, yet close relatives are often regeneration incompetent. Why in the face of 'survival of the fittest' some animals regenerate but others do not remains a fascinating question. Planarian flatworms are well known and studied for their ability to regenerate from minute tissue pieces, yet species with limited regeneration abilities have been described even amongst planarians. Here we report the characterization of the regeneration defect in the planarian Dendrocoelum lacteum and its successful rescue. Tissue fragments cut from the posterior half of the body of this species are unable to regenerate a head and ultimately die. We find that this defect originates during the early stages of head specification, which require inhibition of canonical Wnt signalling in other planarian species. Notably, RNA interference (RNAi)-mediated knockdown of Dlac-ß-catenin-1, the Wnt signal transducer, restored the regeneration of fully functional heads on tail pieces, rescuing D. lacteum's regeneration defect. Our results demonstrate the utility of comparative studies towards the reactivation of regenerative abilities in regeneration-deficient animals. Furthermore, the availability of D. lacteum as a regeneration-impaired planarian model species provides a first step towards elucidating the evolutionary mechanisms that ultimately determine why some animals regenerate and others do not.

Cellular characterization of adipose tissue from various body sites of women.

Adipose tissue is the primary site of estrogen biosynthesis in postmenopausal women. The two main histologic components of adipose tissue are mature adipocytes and fibroblasts. Aromatase P450 expressed in the fibroblast component of adipose tissue is responsible for catalyzing conversion of C19 steroids to estrogens. We previously have demonstrated that in women, aromatase expression in adipose tissue of various body sites increases with age and that aromatase expression in the hip is markedly higher than in the abdomen. To determine whether this age- and regional-dependent variation in aromatase expression is caused by an alteration in the ratio of fibroblasts to mature adipocytes, we collected sc adipose tissue samples from 19 women (age range: 21-93 yr) at the time of autopsy. Using a computerized image analysis system, we determined by morphometry the proportions of adipocytes, fibroblasts, and vascular endothelial cells within histologic sections of adipose tissue from midabdomen, both breasts, and both hips. The percentage of each cell component at each body site was expressed as the mean of triplicate replicates. Statistical analysis of our results did not indicate any correlation between advancing age and fibroblast to adipocyte ratios in the breast, abdomen, or hip. Fibroblast to adipocyte ratios were found to be significantly higher in the breast and abdomen compared with the hip ( P < 0.05). No statistical differences were found between the breast and abdomen. These findings suggest that the increase in aromatase expression with advancing age and the higher aromatase expression in the hip compared with the abdomen in women may be caused by alterations in specific signal transduction mechanisms rather than a simple increase in local adipose fibroblast numbers.

Distribution of aromatase P450 transcripts and adipose fibroblasts in the human breast.

The fibroblast component of adipose tissue is the primary extraglandular site of aromatase P450 (P450arom) expression, which is responsible for the conversion of C19 steroids to estrogens. Previously, we have shown positive correlations between the level of P450arom transcripts and the ratio of fibroblasts to mature adipocytes in adipose tissue samples proximal to breast tumors. The present study was conducted to determine the distribution of P450arom messenger ribonucleic acid (RNA) levels and fibroblast to adipocyte ratios in disease-free breasts of premenopausal women. Adipose tissue samples were collected from 3 regions (outer, upper, and inner) of both breasts of 13 women undergoing reduction mammoplasty. The histological composition of adipose tissue (n = 12) was determined by morphometry using a computerized image analysis program. We used a competitive RT-PCR method employing rat P450arom complementary RNA as an internal standard to quantify adipose P450arom transcripts in tissue total RNA samples (n = 11). Overall, 67% of the highest fibroblast to adipocyte ratios and 64% of the highest P450arom transcript levels were detected in an outer breast region, whereas in only 1 patient were the highest values detected in an inner region. Parametric ANOVA showed significant differences between the fibroblast content of the regions [p(F) = 0.037]. This distribution pattern directly correlates with the most common or the least common sites of carcinoma in the breast, the outer and inner regions, respectively. Moreover, a direct relationship was demonstrated between adipose fibroblasts and P450arom transcripts within the breast, in that regions with the highest fibroblast to adipocyte ratios contained the highest P450arom transcript levels (by ANOVA of contrast variables, P = 0.0009). These results suggest that, similar to our previous findings in the breast bearing a tumor, adipose tissue aromatase expression in the disease-free breast is determined by the local ratio of fibroblasts to adipocytes.

Correlation of coronary angioscopic to angiographic findings in coronary artery disease.

An Olympus ultrathin fiberscope, 1.8 mm outer diameter, was inserted intraluminally into 11 stenoses of the left anterior descending and circumflex coronary arteries in 8 patients at coronary bypass surgery. Intraluminal views were obtained by coupling the angioscope to a color video camera and videotape recorder, and compared with preoperative coronary angiographic findings in right and left anterior oblique views. Atherosclerotic plaque was observed as yellow-white mass attached onto the luminal lining, which may be large enough to virtually obliterate the vascular lumen. Angioscopy provided a topographic view and cross-sectional picture of stenosis not observed by angiography. Single-plane angioscopic cross-sectional stenotic lumens correlated well (r = 0.90, p less than 0.001) with calculated angiographic luminal narrowings. However, with subtotal obstruction, lesion length must be assessed angiographically. Coronary angioscopy can be a useful adjunct to angiography by providing the added dimension of the true cross-sectional view of obstruction.

Effects of laser radiation on the morphology of human coronary atherosclerotic disease.

Laser energy delivered through optical fibers can produce potent controlled thermal dissolution of human coronary obstructive disease, thus widening the stenotic vascular lumen. The ease of vaporization and penetration depends not only on the physical properties of the laser beam but also on the physical characteristics of the atherosclerotic plaque. Lipid-laden plaques are more easily vaporized compared with plaques that are heavily calcified. In atherosclerotic animal models studied in vivo, laser radiation produced a charred lining around the evacuated area and rapid regeneration of a new endothelial lining. After several weeks, the laser-induced crater was still evident, and thrombogenesis was not a significant complication. Focal aneurysmal dilatation may develop when there is thermal injury of the medial layer, and acute perforation can occur if severe laser burn is extended beyond the adventitial layer. Further technical advances and achievements are needed before laser recanalization becomes a clinical reality.

Laser therapy of coronary artery obstructions.

Laser energies can be transmitted through flexible optical fiber to vaporize and penetrate coronary atherosclerotic and thrombotic obstructions. There are risks and complications involved in this therapy, however, including perforation, aneurysm formation, and thromboembolic risks, and further research is needed to render the laser recanalization procedure safe.

The portrayal of bariatric surgery in the UK print media.

BACKGROUND: Bariatric and metabolic surgery is a recent introduction into mainstream surgical practice. It has been shown to have a beneficial effect on the health of an individual and a positive economic impact for society. Nonetheless, bariatric surgery faces a problem of perception from both the public and healthcare commissioners. The media functions as an interface between the medical community, government and the public. It therefore plays a critical role in shaping public opinion regarding health issues. METHODS: Articles relating to bariatric surgery in the ten most frequently read UK daily newspapers were assessed over a 24-month period (January 2010-December 2011). Each article was rated via a five-point scale from very negative (1) to very positive (5) by two independent assessors to produce an average score. RESULTS: A total of 197 relevant articles were identified and analysed for content. Sixty-four (33 %) of all articles were negatively slanted (mean score 1-2.5), 105 (53 %) were positive (mean score 3.5-5) and 28 (14 %) were neutral (mean score 2.5-3.5). The average score of all articles was 3.3 (neutral, but slightly positive). CONCLUSIONS: The print media will influence public perceptions of bariatric surgery. There is huge variation in how bariatric surgery is reported, but overall the coverage is neutral. We feel that negative reportage distorts the overall awareness of bariatric surgery and may affect both how and when the obese seek medical intervention.

Adaptation of head posture in response to relocating the center of mass: a pilot study.

Relationships have been established between head posture and craniofacial morphology in both adults and children. The determinants of head posture are not yet understood. Does posture dictate form, or vice versa? This pilot study investigates the short-term effect of artificial forward relocation of the center of the mass of the head on postural adaptation in the sagittal plane. The observed responses are not systematically uniform and, in fact, are characterized by a lack of consistency and a high degree of intra- and interindividual variability.

Decreased quality of peripheral blood progenitors collected after a peripheral blood progenitor transplant.

The purpose of this study was to determine the quality of peripheral blood progenitor cells (PBPC) collected after an initial autologous PBPC transplant. Tandem autologous transplants have been used in the treatment of several malignancies. Routinely, PBPC have been collected prior to the first transplant and used for both transplants. In the current study, PBPC harvested prior to the first high-dose therapy (HDT) were used as a source of progenitors for transplant 1, and a combination of bone marrow harvested prior to the first course of HDT and PBPC collected approximately 85 days after the first transplant were used to support the second HDT. We analyzed the quality of the PBPC collected 85-120 days after HDT and autologous PBPC transplant. CD34 and colony-forming units granulocyte-macrophage (CFU-GM) contents of those collections were poor, and hematopoietic recovery was more consistent with recovery from a bone marrow transplant than a PBPC transplant. Thirteen of 15 patients received both transplants. Days to absolute granulocyte count of 500 was 10 +/- 1.5 for the first transplant and 13.3 +/- 3.7 for the second (p < 0.01). The number of days to platelet count of 20,000 was 14.3 +/- 10.7 for the first transplant and 18 +/- 7 for the second transplant (p = 0.066). The number of days of total parenteral nutrition (TPN) and intravenous morphine used by patients for the first and second transplants was similar, whereas the length of hospitalization was 21.8 +/- 3.6 for the first transplant and 27.6 +/- 7.8 for the second transplant (NS). In conclusion, it appears that the quality of PBPC collected following a previous PBPC transplant may be compromised.

Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes.

In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

Plant nuclei can contain extensive grooves and invaginations.

Plant cells can exhibit highly complex nuclear organization. Through dye-labeling experiments in untransformed onion epidermal and tobacco culture cells and through the expression of green fluorescent protein targeted to either the nucleus or the lumen of the endoplasmic reticulum/nuclear envelope in these cells, we have visualized deep grooves and invaginations into the large nuclei of these cells. In onion, these structures, which are similar to invaginations seen in some animal cells, form tubular or planelike infoldings of the nuclear envelope. Both grooves and invaginations are stable structures, and both have cytoplasmic cores containing actin bundles that can support cytoplasmic streaming. In dividing tobacco cells, invaginations seem to form during cell division, possibly from strands of the endoplasmic reticulum trapped in the reforming nucleus. The substantial increase in nuclear surface area resulting from these grooves and invaginations, their apparent preference for association with nucleoli, and the presence in them of actin bundles that support vesicle motility suggest that the structures might function both in mRNA export from the nucleus and in protein import from the cytoplasm to the nucleus.

Knowledge representation and problem solution in expert and novice youth baseball players.

The purpose of this study was to examine differences in knowledge representation and problem solutions in expert and novice youth baseball players. Ninety-four players in two age divisions, 7-8 years of age and 9-10 years of age, were assigned to three levels of expertise: high; average; and low skilled. Each subject participated in an interview session to elicit knowledge representation and solutions to five different defensive game situations. Interviews were transcribed and analyzed for content, solution to the problem, errors in problem solution, and qualitative trends. The frequency of advanced solutions to each of the five situations were analyzed in separate chi-square tests for age and expertise. Differences among the levels of expertise were found for the accuracy of solutions to three complex situations. Age was significant for only one situation. Patterns of knowledge content accessed during advanced and less advanced responses indicated both experts and novices were in a beginning stage of developing baseball knowledge structures. Errors in problem solutions indicated children had difficulty monitoring critical conditions and making correct inferences. Players' and teammates' ability to execute baseball skills seemed to influence the content and structure of tactical knowledge accessed during problem solution.

Multiple-photon absorption of 16-microm radiation in UF6 at 300 K.

Fluence-dependent optical-absorption parameters were measured in static room-temperature UF(6) at 12 frequencies in the range 615 to 635 cm(-1) and over a fluence range of 0.02 to 8 mJ/cm(2). All data of the average number of photons absorbed per monomer (eta) as a function of fluence (Phi) were fitted to the empirical relation eta = C(1)(v)PhiC(2) (C(2) = 0.8 +/- 0.1). Addition of diluent (N(2)) increased the absorption.

Applicability of laser to assist coronary balloon angioplasty.

Severe atherosclerotic obstructed coronary artery disease (CAD) may preclude passage of a balloon catheter for transluminal coronary angioplasty (TCA). Since lasers have been shown to effectively vaporize CAD plaque, the initial application of laser to effect a lumen large enough to accommodate the angioplasty catheter for further dilatation was explored. Eleven postmortem human CAD segments which did not permit passage of a 1.33 mm shaft diameter angioplasty catheter were studied. Argon laser radiation (14 to 90 J) transmitted via 400 micron core diameter quartz fiber onto the stenotic channel of 0.58 mm created a vaporized lumen of 1.77 mm (mean increase of 1.31 +/- 0.25 mm, p less than 0.001). The laser procedure allowed the balloon angioplasty catheter to be pushed into the stenosis. TCA was then performed (7 atm, 45 seconds) and expanded the channel to 2.12 mm (additional mean increase of 0.38 +/- 0.07 mm, p less than 0.001). In terms of percent luminal narrowing, laser radiation reduced obstruction from 80% to 45% (mean difference of -38.7 +/- 4.6%, p less than 0.001), and TCA caused a further decrease to 37% (mean difference of -9.3 +/- 1.9%, p less than 0.001). Thus, in tight atherosclerotic lesions, the laser may be useful in creating an initial opening enabling the placement of the balloon angioplasty catheter which, in turn, can further dilate the lased stenotic coronary lumen.

Effects of simultaneous viewing and vaporization of plaques using the steerable, laser-heated metal cap in the atherosclerotic monkey model.

A steerable, fiberoptic catheter coupled to a laser light guide tipped with a metal cap was used. Four monkeys fed an atherogenic diet for 7-8 years were angiographed and were found to have extensive mural plaque in the iliac arteries. Plaque sites in these monkeys were vaporized using the laser-heated metal cap. Energies of 1.5-9 Joules were employed. Application of the energy was tangential of perpendicular to the plaque. Lased sites were examined histologically at 24 hr or at 3 months after treatment. No effect was seen at 1.5 Joules. Three to six Joules tangentially produced a superficial lesion that extended into the tunica intima. Six Joules perpendicularly produced a burn into the tunica adventitia, with damage to the vasavasorum. Nine Joules tangentially produced a burn into the tunica media. Three months after treatment, this lased site showed no stenosis or aneurysm formation.