Regulation of TGF-β1-Induced EMT by Autophagy-Dependent Energy Metabolism in Cancer Cells

Simple Summary

The spread of cancer to other parts of the body is the primary cause of death in most patients. Autophagy is an intracellular maintenance process. Its role in initiating the spread of cancer is still debated. Here, we examined the connection between autophagy and the initial transition of lung cancer cells into the metastatic phenotype, capable of migrating to distant parts of the body. Repressing autophagy reduced the amount of the proteins responsible for this transition but not the expression of their corresponding genes. Therefore, autophagy may regulate the translation of these proteins. We further showed that autophagy involves in regulation of energy mediators, necessary for protein translation. Blocking autophagy and the resulting drop in energy levels diminishes the proteins necessary for initiating metastasis, which represents a potential target of cancer therapy.

Abstract

Metastasis is associated with poor prognosis and is the major cause of death in cancer patients. The epithelial to mesenchymal transition (EMT) is essential for cancer cells to acquire a highly migratory phenotype. Metabolic reprogramming is required to meet the energy demands during this process. Recent studies have indicated that autophagy is involved in EMT, during which cancer cells depend on autophagy activation for survival. However, accumulating evidence indicates that autophagy’s involvement in cancer is context-dependent, acting as either promoter or inhibitor. In this study, we investigated the role of autophagy in supplying energy to support EMT. We induced EMT in Non-small cell lung cancer A549 cells using TGF-β1 with and without autophagy inhibition. Suppression of autophagy activity by knocking down of BECN1 or chloroquine (CQ) treatment inhibited mesenchymal protein expression. Interestingly, TGF-β1 promoted the transcription of target mRNAs, SNAI1, VIM, and CDH2, regardless of autophagy status. The imbalance between protein and mRNA levels indicated the possibility of autophagy-dependent translational regulation. Since protein synthesis consumes large amounts of energy, it is tightly regulated via various cellular signaling pathways such as AMPK and mTOR. Our investigation showed inhibition of autophagy decreased ATP production from OXPHOS and led to the suppression of mRNA translation by phosphorylation of eukaryotic elongation factor 2 (eEF2). These results suggest that A549 non-small cell lung cancer required autophagy to maintain mitochondrial homeostasis during TGF-β1 induced EMT. In conclusion, blocking autophagy decreased energy production and down-regulated proteins synthesis inhibiting TGF-β1 induced EMT.

ARL6IP5 reduces cisplatin-resistance by suppressing DNA repair and promoting apoptosis pathways in ovarian carcinoma

Ovarian carcinoma (OC) is the most lethal gynecological malignancy due to frequent recurrence resulting from cisplatin-resistance. ARL6IP5 is a novel gene implicated to suppress cisplatin-resistance by activating apoptosis and inhibiting DNA repair through XRCC1 and PARP1. We investigated the clinicopathological and prognostic significance of the immunohistochemical ARL6IP5 expression on 79 post-chemotherapy OC patient tissue samples; in vitro, the effect of ARL6IP5 overexpression (OE) and knockdown (KD) on cancer hallmark functions and the effect of ARL6IP5 on the expression of DNA repair and apoptosis-related proteins were observed in OC cells and their cisplatin-resistant (CisR) counterparts. ARL6IP5 expression was significantly associated with chemotherapeutic response and was an independent prognosticator of progression-free and overall survival of high-grade serous OC patients. ARL6IP5-OE decreased cellular proliferation, invasion, migration, adhesion, and increased apoptosis (p < 0.05); the opposite was observed for ARL6IP5-KD. Notably, ARL6IP5-OE reduced cisplatin-resistance of both OC and CisR OC cells, while ARL6IP5-KD increased cisplatin-resistance (p < 0.05). ARL6IP5-OE suppressed the expressions of DNA repair proteins and increased those of pro-apoptotic proteins; the opposite was observed for ARL6IP5-KD. The recombinant ARL6IP5 protein (rARL6IP5) had the greatest apoptotic effect among cisplatin and olaparib, in both OC and CisR OC cells; moreover, rARL6IP5 was the only single agent in CisR OC cells to retain higher apoptotic efficacy compared with control (p < 0.05), indicating that the apoptotic pathway influenced by rARL6IP5 remained effective in CisR OC cells compared to cisplatin and olaparib. In conclusion, we demonstrated that ARL6IP5 is an independent prognosticator of OC patients with cellular functions of a tumor-suppressor, possibly influencing the development of cisplatin-resistance and progression of OC cells through regulation of DNA repair and apoptosis. rARL6IP5 had significantly greater apoptotic efficacy compared to conventional chemotherapeutic agents in both OC and CisR OC cells, suggesting that ARL6IP5 may be a valuable novel chemotherapeutic against CisR OC.

Lidocaine: A Local Anesthetic, Its Adverse Effects and Management

The most widely used medications in dentistry are local anesthetics (LA), especially lidocaine, and the number of recorded adverse allergic responses, particularly of hazardous responses, is quite low. However, allergic reactions can range from moderate to life-threatening, requiring rapid diagnosis and treatment. This article serves as a review to provide information on LA, their adverse reactions, causes, and management.

Combination of Niraparib, Cisplatin and Twist Knockdown in Cisplatin-Resistant Ovarian Cancer Cells Potentially Enhances Synthetic Lethality through ER-Stress Mediated Mitochondrial Apoptosis Pathway

Poly (ADP-ribose) polymerase 1 inhibitors (PARPi) are used to treat recurrent ovarian cancer (OC) patients due to greater survival benefits and minimal side effects, especially in those patients with complete or partial response to platinum-based chemotherapy. However, acquired resistance of platinum-based chemotherapy leads to the limited efficacy of PARPi monotherapy in most patients. Twist is recognized as a possible oncogene and contributes to acquired cisplatin resistance in OC cells. In this study, we show how Twist knockdown cisplatin-resistant (CisR) OC cells blocked DNA damage response (DDR) to sensitize these cells to a concurrent treatment of cisplatin as a platinum-based chemotherapy agent and niraparib as a PARPi on in vitro two-dimensional (2D) and three-dimensional (3D) cell culture. To investigate the lethality of PARPi and cisplatin on Twist knockdown CisR OC cells, two CisR cell lines (OV90 and SKOV3) were established using step-wise dose escalation method. In addition, in vitro 3D spheroidal cell model was generated using modified hanging drop and hydrogel scaffolds techniques on poly-2-hydroxylethly methacrylate (poly-HEMA) coated plates. Twist expression was strongly correlated with the expression of DDR proteins, PARP1 and XRCC1 and overexpression of both proteins was associated with cisplatin resistance in OC cells. Moreover, combination of cisplatin (Cis) and niraparib (Nira) produced lethality on Twist-knockdown CisR OC cells, according to combination index (CI). We found that Cis alone, Nira alone, or a combination of Cis+Nira therapy increased cell death by suppressing DDR proteins in 2D monolayer cell culture. Notably, the combination of Nira and Cis was considerably effective against 3D-cultures of Twist knockdown CisR OC cells in which Endoplasmic reticulum (ER) stress is upregulated, leading to initiation of mitochondrial-mediated cell death. In addition, immunohistochemically, Cis alone, Nira alone or Cis+Nira showed lower ki-67 (cell proliferative marker) expression and higher cleaved caspase-3 (apoptotic marker) immuno-reactivity. Hence, lethality of PARPi with the combination of Cis on Twist knockdown CisR OC cells may provide an effective way to expand the therapeutic potential to overcome platinum-based chemotherapy resistance and PARPi cross resistance in OC.

Chemotherapy Resistance Explained through Endoplasmic Reticulum Stress-Dependent Signaling

Cancers cells have the ability to develop chemotherapy resistance, which is a persistent problem during cancer treatment. Chemotherapy resistance develops through different molecular mechanisms, which lead to modification of the cancer cells signals needed for cellular proliferation or for stimulating an immune response. The endoplasmic reticulum (ER) is an important organelle involved in protein quality control, by promoting the correct folding of protein and ER-mediated degradation of unfolded or misfolded protein, namely, ER-associated degradation. Disturbances of the normal ER functions causes an accumulation of unfolded or misfolded proteins in the ER lumen, resulting in a condition called “ER stress (ERS).” ERS triggers the unfolded protein response (UPR)—also called the ERS response (ERSR)—to restore homeostasis or activate cell death. Although the ERSR is one emerging potential target for chemotherapeutics to treat cancer, it is also critical for chemotherapeutics resistance, as well. However, the detailed molecular mechanism of the relationship between the ERSR and tumor survival or drug resistance remains to be fully understood. In this review, we aim to describe the most vital molecular mechanism of the relationship between the ERSR and chemotherapy resistance. Moreover, the review also discusses the molecular mechanism of ER stress-mediated apoptosis on cancer treatments.

Quercetin Attenuates Manganese-Induced Neuroinflammation by Alleviating Oxidative Stress through Regulation of Apoptosis, iNOS/NF-κB and HO-1/Nrf2 Pathways

Manganese (Mn) is an essential trace element required for the development of human body and acts as an enzyme co-factor or activator for various reactions of metabolism. While essential in trace amounts, excessive Mn exposure can result in toxic accumulations in human brain tissue and resulting extrapyramidal symptoms called manganism similar to idiopathic Parkinson’s disease (PD). Quercetin (QCT) has been demonstrated to play an important role in altering the progression of neurodegenerative diseases by protecting against oxidative stress. This study aimed to investigate the protective effect of QCT on Mn-induced neurotoxicity and the underlying mechanism in SK-N-MC human neuroblastoma cell line and Sprague-Dawley (SD) male rat brain. The results showed that Mn treatment significantly decreased the cell viability of SK-N-MC cell and increased the release of lactate dehydrogenase (LDH), which was attenuated by QCT pretreatment at 10 and 20 µg/mL. Compared to the Mn alone group, QCT pretreatment significantly attenuated Mn-induced oxidative stress, mitochondrial dysfunction and apoptosis. Meanwhile, QCT pretreatment markedly downregulated the NF-κB but upregulated the heme oxygenase-1 (HO-1) and Nrf2 proteins, compared to the Mn alone group. Our result showed the beneficial effect of QCT on hematological parameters against Mn in rat brain. QCT decrease reactive oxygen species (ROS) and protein carbonyl levels and increased Cu/Zn-superoxide dismutase (SOD) activity induced in Mn-treated rats. QCT administration caused a significant reduction in the Mn-induced neuroinflammation by inhibiting the expression of inflammatory markers such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). QCT lowered the Mn elevated levels of various downstream apoptotic markers, including Bax, cytochrome c, cleaved caspase-3 and polymerase-1 (PARP-1), while QCT treatment upregulated anti-apoptotic Bcl-2 proteins and prevented Mn-induced neurodegeneration. Furthermore, administration of QCT (25 and 50 mg/kg) to Mn-exposed rats showed improvement of histopathological alteration in comparison to Mn-treated rats. Moreover, administration of QCT to Mn-exposed rats showed significant reduction of 8-hydroxy-2′-deoxyguanosine (8-OHdG), Bax, activated caspase-3 and PARP-1 immunoreactivity. These results indicate that QCT could effectively inhibit Mn induced apoptosis and inflammatory response in SK-N-MC cells and SD rats, which may involve the activation of HO-1/Nrf2 and inhibition of NF-κB pathway.

Protective role of quercetin against manganese-induced injury in the liver, kidney, and lung; and hematological parameters in acute and subchronic rat models

Manganese (Mn) is an important mineral element required in trace amounts for development of the human body, while over- or chronic-exposure can cause serious organ toxicity. The current study was designed to evaluate the protective role of quercetin (Qct) against Mn-induced toxicity in the liver, kidney, lung, and hematological parameters in acute and subchronic rat models. Male Sprague Dawley rats were divided into control, Mn (100 mg/kg for acute model and 15 mg/kg for subchronic model), and Mn + Qct (25 and 50 mg/kg) groups in both acute and subchronic models. Our result revealed that Mn + Qct groups effectively reduced Mn-induced ALT, AST, and creatinine levels. However, Mn + Qct groups had effectively reversed Mn-induced alteration of complete blood count, including red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, and white blood cells. Meanwhile, the Mn + Qct groups had significantly decreased neutrophil and eosinophil and increased lymphocyte levels relative to the Mn group. Additionally, Mn + Qct groups showed a beneficial effect against Mn-induced macrophages and neutrophils. Our result demonstrated that Mn + Qct groups exhibited protective effects on Mn-induced alteration of GRP78, CHOP, and caspase-3 activities. Furthermore, histopathological observation showed that Mn + Qct groups effectively counteracted Mn-induced morphological change in the liver, kidney, and lung. Moreover, immunohistochemically Mn + Qct groups had significantly attenuated Mn-induced 8-oxo-2′-deoxyguanosine immunoreactivity. Our study suggests that Qct could be a substantially promising organ-protective agent against toxic Mn effects and perhaps against other toxic metal chemicals or drugs.

β-Cell protection and antidiabetic activities of Crassocephalum crepidioides (Asteraceae) Benth. S. Moore extract against alloxan-induced oxidative stress via regulation of apoptosis and reactive oxygen species (ROS)

Background

Medicinal plants are becoming more popular in the treatment of various diseases because of the adverse effects of the current therapy, especially antioxidant plant components such as phenols and flavonoids have a protective role against oxidative stress-induced degenerative diseases like diabetes. Thus, the purpose of this study was to investigate β-cell protection and antidiabetic activities of Crassocephalum crepidioides (Asteraceae) Benth. S. Moore.

Method

The in-vitro study was conducted by the pancreatic β-cell culture and α-amylase inhibition technique which includes two methods, namely starch-iodine method and 3,5-dinitrosalicylic acid (DNSA) method. On the other hand, the in-vivo study was performed by oral glucose tolerance test (OGTT) method and alloxan-induced diabetes method by using Wistar albino rat. At the end pancreatic specimens were removed and processed for histopathological study.

Result

The plant extract showed significant (*p < 0.05, **p < 0.01) effect on hyperglycemia as compared to standard (Gliclazide) in OGTT. The plant extract showed efficient protection activity of pancreatic β-cell from cell death in INS-1 cell line by significantly reduced (*p < 0.05, **p < 0.01) the levels alloxan-induced apoptosis and intracellular reactive oxygen species (ROS) accumulation. In addition, the plant extract showed a significant (*p < 0.05, **p < 0.01) effect on hyperglycemia by increases in percent of β-cells present in each islet (45% – 60%) compared to the diabetic group.

Conclusion

The result showed that C. crepidioides had β-cell protection and antidiabetic activities in pancreatic β-cell culture and Wistar albino rat.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1697-0) contains supplementary material, which is available to authorized users.

Polyphenolic Extract of Euphorbia supina Attenuates Manganese-Induced Neurotoxicity by Enhancing Antioxidant Activity through Regulation of ER Stress and ER Stress-Mediated Apoptosis

Manganese (Mn) is an important trace element present in human body, which acts as an enzyme co-factor or activator in various metabolic reactions. While essential in trace amounts, excess levels of Mn in human brain can produce neurotoxicity, including idiopathic Parkinson’s disease (PD)-like extrapyramidal manganism symptoms. This study aimed to investigate the protective role of polyphenolic extract of Euphorbia supina (PPEES) on Mn-induced neurotoxicity and the underlying mechanism in human neuroblastoma SKNMC cells and Sprague-Dawley (SD) male rat brain. PPEES possessed significant amount of total phenolic and flavonoid contents. PPEES also showed significant antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and reducing power capacity (RPC) assays. Our results showed that Mn treatment significantly reduced cell viability and increased lactate dehydrogenase (LDH) level, which was attenuated by PPEES pretreatment at 100 and 200 µg/mL. Additionally, PPEES pretreatment markedly attenuated Mn-induced antioxidant status alteration by resolving the ROS, MDA and GSH levels and SOD and CAT activities. PPEES pretreatment also significantly attenuated Mn-induced mitochondrial membrane potential (ΔΨm) and apoptosis. Meanwhile, PPEES pretreatment significantly reversed the Mn-induced alteration in the GRP78, GADD34, XBP-1, CHOP, Bcl-2, Bax and caspase-3 activities. Furthermore, administration of PPEES (100 and 200 mg/kg) to Mn exposed rats showed improvement of histopathological alteration in comparison to Mn-treated rats. Moreover, administration of PPEES to Mn exposed rats showed significant reduction of 8-OHdG and Bax immunoreactivity. The results suggest that PPEES treatment reduces Mn-induced oxidative stress and neuronal cell loss in SKNMC cells and in the rat brain. Therefore, PPEES may be considered as potential treat-ment in Mn-intoxicated patients.

ER Stress-Mediated Signaling: Action Potential and Ca(2+) as Key Players

The proper functioning of the endoplasmic reticulum (ER) is crucial for multiple cellular activities and survival. Disturbances in the normal ER functions lead to the accumulation and aggregation of unfolded proteins, which initiates an adaptive response, the unfolded protein response (UPR), in order to regain normal ER functions. Failure to activate the adaptive response initiates the process of programmed cell death or apoptosis. Apoptosis plays an important role in cell elimination, which is essential for embryogenesis, development, and tissue homeostasis. Impaired apoptosis can lead to the development of various pathological conditions, such as neurodegenerative and autoimmune diseases, cancer, or acquired immune deficiency syndrome (AIDS). Calcium (Ca(2+)) is one of the key regulators of cell survival and it can induce ER stress-mediated apoptosis in response to various conditions. Ca(2+) regulates cell death both at the early and late stages of apoptosis. Severe Ca(2+) dysregulation can promote cell death through apoptosis. Action potential, an electrical signal transmitted along the neurons and muscle fibers, is important for conveying information to, from, and within the brain. Upon the initiation of the action potential, increased levels of cytosolic Ca(2+) (depolarization) lead to the activation of the ER stress response involved in the initiation of apoptosis. In this review, we discuss the involvement of Ca(2+) and action potential in ER stress-mediated apoptosis.

Apoptotic and antioxidant activities of methanol extract of Mussaenda roxburghii leaves

roxburghii. Anticancer activity of MMR has been carried out on Ehrlich ascites carcinoma (EAC) cells with three different doses (20, 40 and 60 mg/kg/day) by observing different parameters such as tumor weight, survival time of EAC-bearing mice, growth inhibition of EAC cells, morphological changes and nuclear damage of EAC cells etc. whereas antioxidant activity was determined by measuring total antioxidant, DPPH free radical scavenging, ferrous reducing capacity assay. The extract showed highest anticancer activity at 60 mg/kg day¬-⁻¹(i.p.). It caused 81.4% (P<0.01) cells growth inhibition and reduced tumor burden significantly (78.5%; P<0.001) in comparison to control. It also increased life span of EAC-bearing mice significantly (73.5%; P<0.01). MMR treated EAC cells showed membrane blebbing, chromatin condensation, nuclear fragmentation (apoptotic feature) in Hoechst 33342 staining under fluorescence microscope. DNA fragmentation assay in agarose gel (1.5%) electrophoresis also rectified that it causes EAC cells death by apoptosis. MMR also exhibited moderate antioxidant properties in dose dependent manner. Thus, this plant can therefore be considering a resource for natural chemo-preventive drugs as well as a possible pharmaceutical supplement.

Electromagnetic wave scattering from a rough interface above a chiral medium: generalized telegraphists' equations

Using complete modal expansions for the electromagnetic fields above and below a rough interface between free space and chiral media and on imposing exact boundary conditions at the interface, Maxwell's equations are converted into generalized telegraphists' equations for the wave amplitudes of different species of waves (radiation far fields, lateral, and surface waves). The local basis functions, used in the complete modal expansions, are functions of the fluctuating surface height and medium parameters. The generalized telegraphists' equations are coupled first-order differential equations for the forward- and backward-traveling wave amplitudes. The coupling between the different species of waves is due to the fluctuations of the rough surface height and medium parameters. A Taylor series expansion of the surface element scattering matrix in terms of the chiral parameter is used to distinguish between depolarization due to surface roughness and the chiral properties of the medium. The analysis has applications in remote sensing and identification of biological and chemical materials through their optical activity.

Electromagnetic wave scattering from a rough interface above a chiral medium: generalized field transforms

In order to derive full-wave solutions for electromagnetic wave scattering from rough interfaces between achiral media (free space for instance) and chiral media that satisfy generalized constitutive relations, it is necessary to employ complete modal expansions for the electromagnetic fields above and below the interface. To this end, the familiar Fourier transforms of the fields are expressed as generalized field transforms consisting of the radiation term, the lateral waves, and the surface waves. Maxwell's equations are converted into generalized telegraphists' equations [in the companion paper (this issue), J. Opt. Soc. Am. A 30, 335 (2013)] upon the imposition of exact boundary conditions. These telegraphists' equations are coupled first-order differential equations for the forward- and backward-traveling wave amplitudes associated with all the different species of waves (radiation, lateral, and surface waves) excited at the surface of the chiral medium. The analysis presented here includes the completeness and orthogonal relations of the basis functions associated with the modal expansions. This work is used to distinguish between depolarization due to the chiral properties of the medium and depolarization due to surface irregularities. It has applications in remote sensing and identification of biological and chemical materials based on their optical activity.

Double-scatter cross sections for two-dimensional random rough surfaces that exhibit backscatter enhancement

Full-wave solutions are given for the single- and double-scatter radar cross sections for two-dimensional random rough surfaces. High-frequency approximations are used for the double-scatter cross sections in order to express them as numerically tractable four-dimensional integrals. The major contributions to the double-scatter cross sections are associated with the quasi-parallel and quasi-antiparallel double-scatter paths. They come from the neighborhoods of specular points. The enhancement of the backscatter cross sections, which is associated with the quasi-antiparallel double-scatter paths, is observed for both the like- and cross-polarized cross sections.

Reagents for the chemical development of latent fingerprints: scope and limitations of benzo[f]ninhydrin in comparison to ninhydrin

Benzo[f]ninhydrin was compared to ninhydrin for fingerprint development on paper. Overall, the performance of ninhydrin on exhibits was slightly better than that of benzo[f]ninhydrin. The significant advantages of the benzo[f]ninhydrin over ninhydrin were the much stronger fluorescence it gave after treatment with zinc salts and a slightly quicker reaction under ambient conditions. This fluorescence is, however, similar to that obtained with other reagents, such as DFO or ninhydrin analogs. These advantages apparently are not sufficient to justify regular usage of benzo[f]ninhydrin, especially when one considers its low solubility and high cost.

Computations of the Mueller matrix elements for scattering from layered structures with rough surfaces, with applications to optical detection

A full-wave method is used to evaluate the Mueller matrix elements for scattering from layered structures with random rough surfaces. These provide a database for applications in optical detection over a broad range of rough surface statistical parameters. They can be used to determine the optimal frequencies and incident angles that provide most reliable measurements for optical detection. The elements of the Mueller matrix that are most sensitive to medium parameters of the layered structures can also be identified. Contributions from individual terms of the full-wave solutions are shown to have distinct physical interpretations.

Scattering by layered structures with rough surfaces: comparison of polarimetric optical scatterometer measurements with theory

A laboratory model of a layered structure with a rough upper surface (a glass microscope slide cut with a diamond saw) is used to obtain optical polarimetric data. Scatterometer measurements were made of all the Mueller matrix elements associated with light scattered in arbitrary directions. (A preliminary measurement of scattering from a smooth opaque gold film on a silicon wafer was used to validate the calculation of the Mueller matrix elements.) These measurements are compared with corresponding analytical solutions based on the full-wave approach. Physical interpretations of the analytical solutions that account for scattering upon reflection and transmission across rough interfaces are given in a companion paper. The agreement between calculations and measurements suggests that the full wave, polarimetric solutions can provide a reliable database for electromagnetic detection of rough surfaces in remote-sensing applications.

Structural plasticity of optic synapses in the rat suprachiasmatic nucleus: adaptation to long-term influence of light and darkness

Synapses of optic afferents (optic synapses) in the suprachiasmatic nucleus of hooded rats were morphometrically evaluated after exposing the animals to 12 h, 14 days, 2 months, and 8 months of constant light (light rats) and darkness (dark rats). Compared with dark rats, optic synapses from light rats have larger boutons with larger mitochondria, more clear vesicles, fewer dense-core vesicles and front-line vesicles, smaller presynaptic dense projections, a smaller amount of postsynaptic density material, a smaller relative number of Gray-type I (asymmetric) junctions, a greater relative number of Gray-type II (symmetric) junctions, as well as more and larger mitochondria in the postsynaptic dendrites. Junctions of optic synapses are mostly straight, but the small number of positively curved contacts are more flattened in light rats than in dark rats. An age-related increase in the size of presynaptic dense projections was also observed. There are no changes in the sizes of clear and dense-core vesicles, in the size of synaptic junctions and their numerical density in area, and in the unspecific contact area between pre- and postsynaptic elements. The changes in optic boutons are characteristic for activated and relatively disused synapses with a slow, tonic firing rate. It appears that (1) the amount of postsynaptic density material is proportional to the strength of Gray-type I synapses, and that (2) some excitatory optic synapses become inhibitory after long-term activity, whereas some inhibitory synapses turn into excitatory contacts after long-term disuse.

Personal and domestic hygiene and its relationship to the incidence of diarrhoea in south Sumatera

The association of risk factors and diarrhoeal disease incidence among children less than 3 years of age in District Rambutan, South Sumatera, was investigated by a 20-week case-control study of 48 households with a high incidence of diarrhoeal diseases and 111 households with low incidence. Among sociodemographic characteristics, television ownership had a significant negative association with diarrhoeal disease incidence (odds ratio [OR] 3.22). The hygiene behaviour significantly associated with diarrhoeal diseases were: disposing of children's faeces in open places rather than in a latrine (OR > 10.47); bathing children in rivers rather than at wells (OR 2.88); children eating with their hands rather than with spoons (OR 5.6); household members defecating in open places rather than a latrine (OR 2.56); house without sewage system (OR 6.98). To control diarrhoeal disease in the study area, we suggest targeting three groups of behaviour for modification: those related to a) faeces disposal, b) sanitary drainage, and c) handwashing with soap and using spoons for eating.

Identification of contaminant coatings over rough surfaces using polarized infrared scattering

An optical technique to identify the presence of chemical coatings over rough surfaces is described. It is based on the selective use of elements of the 4 x 4 Mueller matrix. The full-wave theory of electromagnetic scattering is used to predict six independent Mueller elements from randomly rough uncoated (dry) and coated (wet) surface materials as functions of the media complex dielectric coefficients, backscattering angle, and midinfrared wavelengths of laser-beam excitations that are polarization modulated. The set of independent elements at beam wavelengths and backscattering angles [M(mn) (lambda(i), lambda(i))] most sensitive to i optically thick contaminant coatings are statistically obtained from the full-wave database, and detection-parameter sets [lambda(i), lambda(i)] are inputs to another algorithm designed to identify the contaminant coating (when present and interacted by the irradiating beams). These algorithms facilitate the operation of a multi-CO(2) laser-ellipsometer facility now under development at the U.S. Army Chemical Research, Development, and Engineering Center for the remote detection of chemical or biological surface contaminants.

An epidemiological study of mental health and socioeconomic conditions in Sumatera, Indonesia

A mental health survey was conducted in Palembang, Indonesia, to test the hypothesis that rapid socioeconomic and cultural change is detrimental to mental health. The 30-item General Health Questionnaire, translated into Bahasa Indonesia, was administered to a probability sample of 1670 adults (94.9% of the target sample). The Present State Examination was conducted on a weighted subsample of 100, using a 2-phase design. Overall morbidity rates were surprisingly similar to those in industrialized countries. A strong association was found between psychological symptoms and poverty. Persons belonging to communities that had progressed substantially in standards of living had fewer symptoms. The evidence points to a possibly beneficial effect of economic progress on mental health. Longitudinal data are needed to confirm this.

Backscatter cross sections for randomly oriented metallic flakes at optical frequencies: full wave approach

The backscatter cross sections for randomly oriented metallic flakes are derived using the full wave approach. The metallic flakes are characterized by their surface height spectral density function. Both specular point and Bragg scattering at optical frequencies are accounted for in a self-consistent manner. It is shown that the average normalized backscatter cross sections (per unit volume) for the randomly oriented metallic flakes are larger than that of metallic spheres.