Dark scene elements strongly influence cuttlefish camouflage responses in visually cluttered environments.

This study investigated how cuttlefish (Sepia officinalis) camouflage patterns are influenced by the proportions of different gray-scales present in visually cluttered environments. All experimental substrates comprised spatially random arrays of texture elements (texels) of five gray-scales: Black, Dark gray, Gray, Light gray, and White. The substrates in Experiment 1 were densely packed arrays of square texels that varied over 4 sizes in different conditions. Experiment 2 used substrates in which texels were disks separated on a homogeneous background that was Black, Gray or White in different conditions. In a given condition, the histogram of texel gray-scales was varied across different substrates. For each of 16 cuttlefish pattern response statistics c, the resulting data were used to determine the strength with which variations in the proportions of different gray-scales influenced c. The main finding is that darker-than-average texels (i.e., texels of negative contrast polarity) predominate in controlling cuttlefish pattern responses in the context of cluttered substrates. In Experiment 1, for example, substrates of all four texel-sizes, activation of the cuttlefish "white square" and "white head bar" (two highly salient skin components) is strongly influenced by variations in the proportions of Black and Dark gray (but not Gray, Light gray, or White) texels. It is hypothesized that in the context of high-variance visual input characteristic of cluttered substrates in the cuttlefish natural habitat, elements of negative contrast polarity reliably signal the presence of edges produced by overlapping objects, in the presence of which disruptive pattern responses are likely to achieve effective camouflage.

Caregiver burden for informal caregivers of patients with dementia: A systematic review.

BACKGROUND: Dementia is an irreversible illness. The caregiver is expected to assume increased responsibility as the condition of the person with dementia declines. It is important to explore the factors constituting caregiver burden on the informal caregivers of people with dementia. AIMS: The purpose of this article is to identify the factors constituting caregiver burden on the informal caregivers of people with dementia living in the community. METHODS: A systematic review of the four databases, including PubMed, PsycINFO, CINAHL and the Cochrane Library, was carried out to access relevant articles published between 2003 and 2012. Twenty-one articles met the inclusion criteria of this study. RESULTS: Behavioural problems or psychological symptoms were the primary factor of the person with dementia that is associated with caregiver burden. Caregiver socio-demographical factors and psychological factors were the two primary factors of the caregiver burden. LIMITATIONS: Several results of this study were based on studies that had their own limitations. Furthermore, the concept of caregiver 'burden' was not clearly defined in some of the studies; instead, the term was broadly defined. CONCLUSION: Factors of caregiver burden in regard to people with dementia living in the community were clarified in this review study. By identifying all of the factors, healthcare professionals can deliver appropriate assistance to relieve caregiver burden and improve the quality of caregiving for people with dementia. IMPLICATIONS FOR NURSING AND HEALTH POLICY: It is important to identify the factors of the burden on the caregivers of people with dementia living in the community to prevent early nursing home placement, deterioration of caregiver's health and reduce the adverse health outcomes for care recipients. A health-related policy should be formulated to help informal caregivers receive more professional assistance. Training opportunities should be provided for family caregivers to reduce the impact of caregiving on the delivery of effective care.

Do older adults become more depressed with age in Taiwan? The role of social position and birth cohort.

BACKGROUND: Depression is one of the most commonly encountered mental health problems during older adulthood. This study examines differences in depressive symptom trajectories among older Taiwanese adults across two birth cohorts (1920-1924 and 1925-1929), and explores the relationships between socioeconomic position (SEP) variables and symptom trajectories. METHODS: Data from the Taiwan Longitudinal Study on Aging (TLSA) collected between 1989 and 2003 were analysed. The nationally representative sample is composed of community-living adults (n = 2458) in Taiwan aged 60 years and above. Two distinct domains of depressive symptomatology, negative affect and lack of positive affect, assessed by the short form of the Center of Epidemiological Studies-Depression (CES-D) scale were used for all the analyses. Growth curve models were employed to assess the trajectories of depressive symptoms over time. RESULTS: The relationship between ageing and depressive symptoms appeared linear with a minor curvilinear effect. The depressive symptoms in negative affect increased with age (mean linear growth rate = 0.26, p<0.001) but levelled off (mean quadric growth rate = -0.01, p<0.001), while the symptoms in lack of positive affect displayed an opposite trend. The effects of SEP variables also differed by cohort and outcome domain. CONCLUSIONS: Remaining active, living with family and having a high level of education are associated with positive affect later in life, while financial strain and poor health are strongly related to negative affect. These results underline the continued role that SEP plays in psychological adjustment over the course of one's life, independently of ageing.

Cephalopod dynamic camouflage: bridging the continuum between background matching and disruptive coloration.

Individual cuttlefish, octopus and squid have the versatile capability to use body patterns for background matching and disruptive coloration. We define--qualitatively and quantitatively--the chief characteristics of the three major body pattern types used for camouflage by cephalopods: uniform and mottle patterns for background matching, and disruptive patterns that primarily enhance disruptiveness but aid background matching as well. There is great variation within each of the three body pattern types, but by defining their chief characteristics we lay the groundwork to test camouflage concepts by correlating background statistics with those of the body pattern. We describe at least three ways in which background matching can be achieved in cephalopods. Disruptive patterns in cuttlefish possess all four of the basic components of 'disruptiveness', supporting Cott's hypotheses, and we provide field examples of disruptive coloration in which the body pattern contrast exceeds that of the immediate surrounds. Based upon laboratory testing as well as thousands of images of camouflaged cephalopods in the field (a sample is provided on a web archive), we note that size, contrast and edges of background objects are key visual cues that guide cephalopod camouflage patterning. Mottle and disruptive patterns are frequently mixed, suggesting that background matching and disruptive mechanisms are often used in the same pattern.

The structure and possible functions of the milkfish Chanos chanos adipose eyelid.

Basic histological sections (with different staining methods) and scanning electron microscopy (SEM) examinations showed that there were three distinctive layers in the adipose eyelid of milkfish Chanos chanos, which is found in the cephalie region and covers the entire eye. The outer and inner layers were epithelial tissues and the middle layer was composed of connective tissue formed by type I collagen fibrils. No adipose tissue was found in any of the three layers of the so-called adipose eyelid. Examination by transmission spectrophotometer showed that the adipose tissue could filter out ambient light with a wavelength shorter than 305 nm. A photoretinoscope was used to investigate whether the adipose eyelid influenced the mechanism of eye focusing. Eye diopter values did not differ before or after eyelid removal, which indicated that the adipose eyelid did not play a role in eye focusing. In light of these findings, it is suggested that the adipose eyelid serves to block exposure of harmful ultraviolet light into eyes and may also to offer some protection against impact to the eye in the aquatic environment.

Clinic appointment attendance for sexually transmitted infection screening among Filipina sex workers: a multilevel analysis.

This study evaluates putative individual- and contextual-level social risk factors that may influence the likelihood that Filipina female sex workers (FSWs) attend and utilize health services for STI screening. Face-to-face interviews were conducted with 1004 FSWs and their 86 employers. Research staff also collected clinic appointment attendance data. Hierarchical linear modelling was used to estimate the simultaneous effects of individual- and workplace-level factors. Results showed that both individual- and contextual-level characteristics were associated with STI screening appointment attendance. Individual characteristics found to have significant effects on clinic attendance included occupation, income, length of work and commercial sex involvement. City of establishment was a workplace characteristic significantly associated with appointment attendance. In addition to cross-level interactions, the impact of individual-level occupation depended upon characteristics of the workplace. These findings suggest that individual health service utilization is contingent upon contextual-level risk factors in the workplace. Intervention implications aimed at increasing clinic attendance are discussed.

Transthoracic and transesophageal echocardiographic diagnosis of aneurysm of the sinus of Valsalva: a review of five year experience.

BACKGROUND: Aneurysms of the sinus of Valsalva (SVA) are uncommon congenital lesions. The clinical presentations vary from asymptomatic to progressive heart failure following rupture of the aneurysm into an adjacent cardiac chamber. Retrograde aortogram is the diagnostic tool of choice preoperatively. Recent studies have demonstrated that the SVA can be accurately diagnosed using transthoracic two-dimensional, and color Doppler flow mapping, even for surgical preparation without cardiac catheterization. We report our 5-year experience of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of SVA. METHODS: Eleven adult patients with SVA with or without rupture were studied using both TTE and TEE. All of the diagnoses were subsequently comfirmed by either cardiac catheterization or surgical findings. RESULTS: Aneurysms originated in the right coronary sinus (n = 9) and noncoronary sinus (n = 2); they ruptured into the right ventricle in 5 patients and the right atrium in 5 patients. An unruptured right SVA was noted in 1 patient. Both TTE and TEE could identify the site of the aneurysm, rupture sites, and the receiving chamber equally well. Co-existent cardiac lesions included 11 cases of valvular aortic regurgitation (mild in 7, moderate in 2 and severe in 2). Two cases of perimembranous type ventricular septal defect (VSD) and 6 cases of supracristal type VSD (including 1 case of tetraology of Fallot, 3 supracristal, 1 muscular and 1 subaortic) were noted. Three cases were complicated with valvular vegetations (1 aortic valve, 1 aortic and tricuspid valve and 1 aortic and pulmonic valve). One patient had patent ductus arteriosus and 2 patients had pulmonic valvular stenosis. CONCLUSIONS: TEE provides clearer definition for the detailed anatomy of the ruptured sac and co-existent cardiac lesions than TTE through high resolution and closer approach. We conclude that TEE is a powerful complementary diagnostic tool in the evaluation of patients with SVA. TEE also provides additionally useful information for guiding the surgical approach and for assessing the operative results even without cardiac catheterization.

HIV type 1 Tat inhibits tumor necrosis factor alpha-induced repression of tumor necrosis factor receptor p55 and amplifies tumor necrosis factor alpha activity in stably tat-transfected HeLa Cells.

The human immunodeficiency virus type 1 (HIV-1) Tat protein is a key regulatory protein in the HIV-1 replication cycle. Tat interacts with cellular transcriptional factors and cytokines, such as tumor necrosis factor (TNF-alpha), and alters the expression of a variety of genes in HIV-1-infected and noninfected cells. To further elucidate the mechanisms by which HIV-1 Tat amplifies the activity of TNF-alpha, we transfected the HIV-1 tat gene into an epithelial (HeLa) cell line. We observed that Tat-expressing cells had increased NF-kappa B-dependent trans-activational activity due to enhanced NF-kappa B--DNA binding in response to TNF-alpha treatment. Tumor necrosis factor receptor (TNFR) p55 was the prominent receptor, as neutralizing antibodies to TNFR p55, but not to TNFR p75, blocked TNF-alpha-mediated NF-kappa B activation. Furthermore, tat-transfected cells were more sensitive to TNF-alpha-induced cytotoxicity and only the neutralizing antibodies to TNFR p55 completely protected the cells. To determine whether TNFR p55 was involved in amplification of cellular response to TNF-alpha by HIV-1 Tat, we investigated the effect of TNF-alpha on TNFR p55 expression in the tat-transfected cells. TNF-alpha treatment resulted in a reduction in both TNFR p55 mRNA and protein levels in the control cells but not in the tat-transfected cells as determined with Northern blot and Western blot analyses, respectively. Our results indicate that HIV-1 Tat may inhibit TNF-alpha-induced repression of TNFR p55 and thereby amplify TNF-alpha activity in these stably transfected cells.

Cuttlefish camouflage: visual perception of size, contrast and number of white squares on artificial checkerboard substrata initiates disruptive coloration.

We investigated some visual background features that influence young cuttlefish, Sepia pharaonis, to change their skin patterning from 'general resemblance' of the substratum to disruptive coloration that breaks up their body form. Using computer-generated black/white checkerboard patterns as substrata, we first found that the size of the white squares had to be within a certain narrow range (relative to the size of the cuttlefish 'white square') for the animal to exhibit disruptive skin patterning. Second, given the appropriate size of checker, cuttlefish regulated their disruptive skin patterns according to the contrast between white and black squares. Third, by manipulating the number of white squares on a black background, we found that as few as four white squares among 316 black squares (or 1.25%) produced disruptive patterning, yet increasing the number of white squares to 20, 40 or 80 did not increase the frequency of appearance of the cuttlefish 'white square', but only its clarity of expression. These results demonstrate that the size, contrast and number of white objects in the surrounding substratum influence the production and expression of disruptive skin patterns in young cuttlefish.

Melatonin prevents endotoxin-induced circulatory failure in rats.

The pineal secretory product melatonin was found to exert protective effects in septic shock. In a host infected by bacterial lipopolysaccharide (LPS), the expression and release of proinflammatory tumor necrosis factor-alpha (TNF-alpha) is rapidly increased, suggesting that TNF-alpha is associated with the etiology of endotoxic shock. Recent reports show that the expression of NO synthase (NOS) II and the production of superoxide anion (O2*-) also contribute to the pathophysiology of septic shock. In the present study we demonstrate that melatonin prevents circulatory failure in rats with endotoxemia and improves survival in mice treated with a lethal dose of LPS. The beneficial hemodynamic effects of melatonin in the endotoxemic animal appear to be associated with the inhibition of (i) the release of TNF-alpha in plasma, (ii) the expression of NOS II in liver, and (iii) the production of O2*- in aortae. In addition, the infiltration of polymorphonuclear neutrophils into the liver from the surviving LPS mice treated with melatonin was reduced. Thus, our results support the clinical use of melatonin in endotoxemia.

Eye design and color signaling in a stomatopod crustacean Gonodactylus smithii.

Many species of stomatopod crustaceans have multiple spectral classes of photoreceptors in their retinas. Behavioral evidence also indicates that stomatopods are capable of discriminating objects by their spectral differences alone. Most animals use only two to four different types of photoreceptors in their color vision systems, typically with broad sensitivity functions, but the stomatopods apparently include eight or more narrowband photoreceptor classes for color recognition. It is also known that stomatopods use several colored body regions in social interactions. To examine why stomatopods may be so 'concerned' with color, we measured the absorption spectra of visual pigments and intrarhabdomal filters, and the reflectance spectra from different parts of the bodies of several individuals of the gonodactyloid stomatopod species, Gonodactylus smithii. We then applied a model of multiple dichromatic channels for color encoding to examine whether the finely tuned color vision was specifically co-evolved with their complex color signals. Although the eye design of stomatopods seems suitable for detecting color signals of their own, the detection of color signals from other animals, such as reef fishes, can be enhanced as well. Color vision in G. smithii is therefore not exclusively adapted to detect its own color signals, but the spectral tuning of some photoreceptors (e.g. midband Rows 2 and 3) enhances the contrast of certain color signals to a large enough degree to make co-evolution between color vision and these rather specific color signals likely.

Identification of c-myc responsive genes using rat cDNA microarray.

c-Myc functions through direct activation or repression of transcription. Using cDNA microarray analysis, we have identified c-Myc-responsive genes by comparing gene expression profiles between c-myc null and c-myc wild-type rat fibroblast cells and between c-myc null and c-myc null cells reconstituted with c-myc. From a panel of 4400 cDNA elements, we found 198 genes responsive to c-myc when comparing wild-type or reconstituted cells with the null cells. The plurality of the named c-Myc-responsive genes that were up-regulated, including 30 ribosomal protein genes, are involved in macromolecular synthesis and metabolism, suggesting a major role of c-Myc in the regulation of protein synthetic and metabolic pathways. When ectopically overexpressed, c-Myc induced a different and smaller set of c-Myc-responsive genes as compared with the physiologically expressed c-Myc condition. Thus, these results from expression profiling suggest a new primary function for c-Myc and raise the possibility that the physiological and transforming functions of c-myc may be separable.

Characterization of natural illuminants in forests and the use of digital video data to reconstruct illuminant spectra.

We describe illumination spectra in forests and show that they can be accurately recovered from recorded digital video images. Natural illuminant spectra of 238 samples measured in temperate forests were characterized by principal-component analysis. The spectra can be accurately approximated by the mean and the first two principal components. Compared with illumination under open skies, the loci of forest illuminants are displaced toward the green region in the chromaticity plots, and unlike open sky illumination they cannot be characterized by correlated color temperature. We show that it is possible to recover illuminant spectra accurately from digital video images by a linear least-squares-fit estimation technique. The use of digital video data in spectral analysis provides a promising new approach to the studies of the spatial and temporal variation of illumination in natural scenes and the understanding of color vision in natural environments.

Spectral tuning of dichromats to natural scenes.

Multispectral images of natural scenes were collected from both forests and coral reefs. We varied the wavelength position of receptors in hypothetical dichromatic visual systems and, for each receptor pair estimated the percentage of discriminable points in natural scenes. The optimal spectral tuning predicted by this model results in photoreceptor pairs very like those of forest dwelling, dichromatic mammals and of coral reef fishes. Variations of the natural illuminants in forests have little or no effect on optimal spectral tuning, but variations of depth in coral reefs have moderate effects on the spectral placement of S and L cones. The ratio of S and L cones typically found in dichromatic mammals reduces the discriminability of forest scenes; in contrast, the typical ratio of S and L cones in coral reef fishes achieves nearly the optimal discrimination in coral reef scenes.

Color signals in natural scenes: characteristics of reflectance spectra and effects of natural illuminants.

Multispectral images of natural scenes were collected from both forests and coral reefs to represent typical, complex scenes that might be viewed by modern animals. Both reflectance spectra and modeled visual color signals in these scenes were decorrelated spectrally by principal-component analysis. Nearly 98% of the variance of reflectance spectra and color signals can be described by the first three principal components for both forest and coral reef scenes, which implies that three well-designed visual channels can recover almost all of the spectral information of natural scenes. A variety of natural illuminants affects color signals of forest scenes only slightly, but the variation in ambient irradiance spectra that is due to the absorption of light by water has dramatic influences on the spectral characteristics of coral reef scenes.

Loss of KAI1 expression in the progression of colorectal cancer.

The transmembrane 4 superfamily member KAI1 (CD82) has been shown to inhibit pulmonary metastases in experimental metastasis models of prostate cancer and melanoma. KAI1 expression is decreased in the progression of common solid epithelial tumors of adulthood, including lung, prostate, breast, esophageal, gastric, pancreatic, and bladder cancers. The purpose of our study was to investigate KAI1 expression in the progression of human colorectal cancer. We first analyzed 20 colorectal cancer cell lines by immunoblot techniques. KAI1 was expressed heterogeneously, with the tumor cell lines having a more complex degree of glycosylation compared with that of the normal colonic tissue. KAI1 was highly expressed in the primary SW480 colon cancer cell line but was down-regulated 15-fold in the matched metastatic SW620 cell line. We also investigated KAI1 protein expression by immunohistochemistry in tissues from 84 patients with colorectal cancer. Each tissue section was assigned a KAI1 mean score (KMS) from 0 to 300 based on the product of the percentage of cells that stained for KAI1 and the intensity of the stain (1, 2, or 3). In 84 patients with colorectal cancer, KAI1 was expressed at high levels in normal colonic mucosa (KMS 226) but was expressed at lower levels in the primary tumors (KMS 65; P < 0.0001). In a subset of 12 patients with stage IV metastatic disease, we observed a progressive down-regulation of KAI1, from the normal adjacent colonic mucosa (KMS 193) to the primary tumor (KMS 72; P = 0.0001) to the liver metastasis (KMS 25; tumor compared with metastasis, P = 0.0135). We found no correlation between loss of KAI1 expression and stage of disease. In 10 patients, we also noted loss of KAI1 expression in the transition from normal colonic mucosa (KMS 237) to adenoma (KMS 174) to carcinoma (KMS 62; P < 0.0167 for all three comparisons). We conclude that the down-regulation of KAI1 occurs early in the progression of colorectal cancer.

Two posttranscriptional pathways that regulate p21(Cip1/Waf1/Sdi1) are identified by HPV16-E6 interaction and correlate with life span and cellular senescence.

The p21((Cip1/Waf1/Sdi1)) protein is a cyclin-dependent kinase inhibitor that is induced in normal human fibroblasts (NHF) following DNA damage, following serum stimulation, and at cellular senescence. Expression of the human papilloma virus 16 E6 oncoprotein in NHF cells results in the loss of the p21 protein, independent of mRNA level under most conditions. The p21 protein levels in NHF-E6 cells remained low following DNA damage or serum stimulation even though mRNA levels increased. In contrast, the p21 protein was transiently induced in NHF-E6 cells at the onset of cellular senescence. Expression of the E6 oncoprotein in transformed cells had no effect on p21 protein levels. This demonstrates that two posttranscriptional pathways regulate expression of p21 protein in NHF cells under different conditions. Disruption of posttranscriptional regulation is correlated with extension of life span, altered cell fate, and transformation.

Comparison between effects of dantrolene and nifedipine on lipopolysaccharide-induced endotoxemia in the anesthetized rats.

Intracellular calcium is an important mediator for regulating the cellular response in endotoxemia. In this study, we investigated the effects of dantrolene and nifedipine, two agents of reducing intracellular calcium levels, on bacterial endotoxin (lipopolysaccharide, LPS; 10 mg/kg i.v.)-induced production of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) as well as hemodynamic changes in the anesthetized rat. Injection of LPS (i) induced biphasic changes of blood glucose and rectal temperature: an initial increased phase (<180 min after injection of LPS) followed by a decreased phase (at 240 or 360 min), (ii) caused a significant fall in mean arterial blood pressure from 119+/-3 mmHg (at time 0) to 73+/-67 mmHg (at 360 min) with a concomitant increase of heart rate, (iii) resulted in a substantial hyporeactivity to norepinephrine (NE) (1 microg/kg i.v.), (iv) increased plasma nitrate (an indicator of NO formation) in a time-dependent manner, and (v) induced bell-shape changes in plasma TNF-alpha levels which reached a peak at 60 min. Pretreatment of animals with dantrolene (1 mg/kg i.v. at 20 min prior to LPS) or nifedipine (20 microg/kg i.v. infusion for 20 min at 20 min prior to LPS) not only attenuated the delayed circulatory failure (e.g. delayed hypotension and vascular hyporeactivity to NE), but also prevented the overproduction of NO caused by LPS in the rat. However, the prevention of NO overproduction by dantrolene, but not by nifedipine, was associated with an inhibition of TNF-alpha production elicited by LPS. Thus, both dantrolene and nifedipine have beneficial hemodynamic effects, although through different mechanisms, in animals with endotoxic shock.

p53-dependent p21 induction following gamma-irradiation without concomitant p53 induction in a human peripheral neuroepithelioma cell line.

We previously generated cell hybrids between a derivative of the E6-containing HeLa cell line and a p53 null peripheral neuroepithelioma (PNET) cell line. Although p53 protein from the hybrids was genotypically wild type, it did not demonstrate wild-type behavior. Therefore, in the present study, we introduced wild-type p53 into the PNET parent to investigate whether p53 retained wild-type function within this cell line. Although the p53 null PNET parent lacked detectable p21 protein, introduction of wild-type p53 resulted in a detectable expression of p21 protein in all clones tested, suggestive of wild-type p53 function. In addition, p53 expression was necessary for induction of p21 in response to irradiation, and, furthermore, we show this induction to occur at the transcriptional level. Although introduction of wild-type p53 seems to be responsible for p21 induction, the overall protein levels of p53 were not induced. The involvement of p53 in up-regulating p21 is further substantiated by the observation that p21 up-regulation was dependent on the introduction of the wild-type protein. Our results suggest that wild-type p53 is capable of up-regulating p21 in response to DNA damage in the absence of p53 induction.