Development and in vitro assessment of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold.

An innovative approach was developed to engineer a multi-layered chitosan scaffold for osteochondral defect repair. A combination of freeze drying and porogen-leaching out methods produced a porous, bioresorbable scaffold with a distinct gradient of pore size (mean = 160-275 µm). Incorporation of 70 wt% nano-hydroxyapatite (nHA) provided additional strength to the bone-like layer. The scaffold showed instantaneous mechanical recovery under compressive loading and did not delaminate under tensile loading. The scaffold supported the attachment and proliferation of human mesenchymal stem cells (MSCs), with typical adherent cell morphology found on the bone layer compared to a rounded cell morphology on the chondrogenic layer. Osteogenic and chondrogenic differentiation of MSCs preferentially occurred in selected layers of the scaffold in vitro, driven by the distinct pore gradient and material composition. This scaffold is a suitable candidate for minimally invasive arthroscopic delivery in the clinic with potential to regenerate damaged cartilage and bone.

Structural, mechanical and swelling characteristics of 3D scaffolds from chitosan-agarose blends.

This study aimed to explore the correlation between mechanical and structural properties of chitosan-agarose blend (Ch-Agrs) scaffolds. Porosity of Ch-Agrs scaffolds was constant at 93%, whilst pore sizes varied between 150 and 550 µm. Pore sizes of the blend scaffolds (150-300 µm) were significantly smaller than for either agarose or chitosan scaffolds alone (ca. 500 µm). Ch50-Agrs50 blend scaffold showed the highest compressive modulus and strength values (4.5 ± 0.4 and 0.35 ± 0.03 MPa) due to reduction in the pore size. The presence of agarose improved the stability of the blends in aqueous media. The increase in compressive properties and residual weight after the TGA test, combined with the reduction in the swelling percentage of the blend scaffolds suggested an interaction between chitosan and agarose via hydrogen bonding which was confirmed using FTIR analysis. All wet blend scaffolds exhibited instant recovery after full compression. This study shows the potential of Ch-Agrs scaffolds for repairing soft tissue.

Community prevalence of chronic respiratory symptoms in rural Malawi: Implications for policy.

BACKGROUND: No community prevalence studies have been done on chronic respiratory symptoms of cough, wheezing and shortness of breath in adult rural populations in Malawi. Case detection rates of tuberculosis (TB) and chronic airways disease are low in resource-poor primary health care facilities. OBJECTIVE: To understand the prevalence of chronic respiratory symptoms and recorded diagnoses of TB in rural Malawian adults in order to improve case detection and management of these diseases. METHODS: A population proportional, cross-sectional study was conducted to determine the proportion of the population with chronic respiratory symptoms that had a diagnosis of tuberculosis or chronic airways disease in two rural communities in Malawi. Households were randomly selected using Google Earth Pro software. Smart phones loaded with Open Data Kit Essential software were used for data collection. Interviews were conducted with 15795 people aged 15 years and above to enquire about symptoms of chronic cough, wheeze and shortness of breath. RESULTS: Overall 3554 (22.5%) participants reported at least one of these respiratory symptoms. Cough was reported by 2933, of whom 1623 (55.3%) reported cough only and 1310 (44.7%) combined with wheeze and/or shortness of breath. Only 4.6% (164/3554) of participants with chronic respiratory symptoms had one or more of the following diagnoses in their health passports (patient held medical records): TB, asthma, bronchitis and chronic obstructive pulmonary disease). CONCLUSIONS: The high prevalence of chronic respiratory symptoms coupled with limited recorded diagnoses in patient-held medical records in these rural communities suggests a high chronic respiratory disease burden and unmet health need.

PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Postnatal reproductive development and the lactocrine hypothesis.

Maternal effects on development can program cell fate and dictate offspring phenotype. Such effects do not end at birth, but extend into postnatal life through signals communicated from mother to offspring in first milk (colostrum). Transmission of bioactive factors from mother to offspring as a specific consequence of nursing defines a lactocrine mechanism. The female reproductive tract is not fully formed at birth (postnatal day = PND 0). Data for ungulates and mice indicate that disruption of development during neonatal life can have lasting effects on the form and function of uterine tissues. Uterine growth and histogenesis proceed in an ovary-independent manner shortly after birth, suggesting that extra-ovarian inputs are important in this process. Data for the pig indicate that lactocrine signals communicated within 12 to 48 h from birth constitute one source of such uterotrophic support. Disruption of lactocrine signaling, either naturally, by limited colostrum consumption, or experimentally, by milk replacer feeding, alters neonatal porcine uterine development and can have negative consequences for reproductive performance in adults. Substantial differences in endometrial and uterine gene expression between colostrum- and replacer-fed gilts were evident by PND 2, when RNA sequencing revealed over 800 differentially expressed, lactocrine-sensitive genes. Lactocrine-sensitive biological processes identified through transcriptomic studies and integrated microRNA-mRNA pathway analyses included those associated with both cell-cell and ESR1 signaling, and tissue development. Evidence for the pig indicates that colostrum consumption and lactocrine signaling are required to establish a normal uterine developmental program and optimal uterine developmental trajectory.

Informal Health Provider and Practical Approach to Lung Health interventions to improve the detection of chronic airways disease and tuberculosis at primary care level in Malawi: study protocol for a randomised controlled trial.

BACKGROUND: In developing countries like Malawi, further investigation is rare after patients with chronic cough test negative for tuberculosis. Chronic airways disease has presentations that overlap with tuberculosis. However, chronic airways disease is often unrecognised due to a lack of diagnostic services. Within developing countries, referral systems at primary health care level are weak and patients turn to unskilled informal health providers to seek health care. Delayed diagnosis and treatment of these diseases facilitates increased severity and tuberculosis transmission. The World Health Organisation developed the Practical Approach to Lung Health strategy which has been shown to improve the management of both tuberculosis and chronic airways disease. The guidelines address the need for integrated guidelines for tuberculosis and chronic airways disease. Engaging with informal health providers has been shown to be effective in improving health services uptake. However, it is not known whether engaging community informal health providers would have a positive impact in the implementation of the Practical Approach to Lung Health strategy. We will use a cluster randomised controlled trial to determine the effect of using the two interventions to improve case detection and treatment of patients with tuberculosis and chronic airways disease. METHODS: A three-arm cluster randomised trial design will be used. A primary health centre catchment population will form a cluster, which will be randomly allocated to one of the arms. The first arm personnel will receive the Practical Approach to Lung Health strategy intervention. In addition to this strategy, the second arm personnel will receive training of informal health providers. The third arm is the control. The effect of interventions will be evaluated by community surveys. Data regarding the diagnosis and management of chronic cough will be gathered from primary health centres. DISCUSSION: This trial seeks to determine the effect of Informal Health Provider and Practical Approach to Lung Health interventions on the detection and management of chronic airways disease and tuberculosis at primary care level in Malawi. TRIAL REGISTRATION: The unique identification number for the registry is PACTR201411000910192--21 November 2014.

Saudáveis trópicos: cidade, higiene e ordem para a Nação em formação [Brasil, 1850-1930] / Healthful tropics: city, hygiene and order for the Nation in formation [Brazil, 1850-1930]

Apresenta uma abordagem sobre a epidemia do cólera. Dentre as várias epidemias que eclodiram ao longo do século XIX no Brasil, a do Cólera de 1855-1856 foi uma das que mais impacto causaram nos campos social, econômico e profissional do país. O rápido alastramento por todas as províncias do Império transformou um território ainda em contrução, assombrou a população de cidades e vilarejos, dizimou dezenas de militares de pessoas, sem distinção social ou 'racial', incluindo vários alunos das faculdades de Medicina então existentes, chamados às linhas de frente de ação contra a epidemia. O que ajudou a deitar por terra a decantada e 'proverbial salubridade' dos trópicos, expondo a debilidade do quadro sanitário das cidades brasileiras. Vários documentos, oficiais sobretudo, puseram em relevo os problemas daí decorrentes, buscando origens, causas, conseqüencias. Dentre eles, destaca-se, pela abrangência da análise e compreensão territorial do fenômeno epidêmico, o 'Relatório acerca da Saúde Pública', publicado em 1856, de autoria de Francisco de Paula Cândido, médico do imperador e ativo publicista da causa higienista em meados do século XIX. [AU]

Systemic lupus erythematosus, meningioma and carcinoma of the cervix--a case report. 1956.

The history of a patient with systemic lupus erythematosus, meningioma and carcinoma of the cervix is presented. Although the meningioma originally masqueraded as a cerebral manifestation of lupus, lack of response to cortisone and progression of symptoms eventually indicated the diagnosis of brain tumor. Carcinoma-in-situ of the cervix was discovered incidentally as a result of routine cervical exfoliative cytological studies. The case history emphasizes the importance of individual evaluation of every patient.

Os "indesejáveis" na cidade: as representaçöes do retirante da seca, Natal, 1890-1930 / The "undesirables" in the city: images of escapers from drought, Natal, 1890-1930

As secas têm sido uma constante na história brasileira e, em especial, naqueles estados que formam o chamado "polígono das secas". Por muito tempo, as elites política e econômica, ao evidenciar e dramatizar este fenômeno em seus discursos, transformaram-na na principal causa do processo migratório do interior flagelado para os centros urbanos mais importantes econômica e politicamente. Para além dos estudos dos processos migratórios, discute as açöes e representaçöes que os retirantes suscitaram nos espaços urbanos ditos civilizados, no caso, a cidade de Natal durante a Primeira República. Estorvo às condiçöes de salubridade do espaço urbano e um embaraço à própria idéia de moderno: tal era a imagem do retirante para uma elite que pretendia criar a cidade moderna nos trópicos. Aos temores da saúde pública se juntaram assim o medo da desordem social e da miséria que näo cabiam neste projeto de modernizaçäo. (AU)

Free radical processes and loss of seed viability during desiccation in the recalcitrant species Quercus robur L.

Loss of moisture in mature seeds of Quercus robur L. was associated with loss of viability, a rise in lipid peroxidation and build-up of free radicals. Radical-initiated damage was largely confined to the embryonic axes as their moisture contents declined to below 47 %. The accumulation of a stable free radical in axial tissue, detected by electron para-magnetic resonance (EPR), was indistinguishable from the EPR response previously shown in a moss on droughting and maize roots on desiccation. A minor higher-field component appeared to represent an intermediate stage in the sequence of free radical reactions associated with loss of water. Using seeds from freshly abscised fruits dried to different moisture contents, protective mechanisms against activated forms of oxygen were monitored in cotyledons and in embryonic axes. The two tissues exhibit distinctly different molecular defences against oxidative attack; that in the cotyledons being predominantly enzymatic, with relatively high and increasing activities of superoxide dismutase and glutathione reductase; that in the axes being largely through the anti-oxidants, ascorbic acid and alpha-tocopherol. We conclude that a decrease in enzymic protection against oxidative attack in the axes, associated with diminishing concentrations of alpha-tocopherol (and depletion of the precursor gamma-tocopherol) as moisture was lost, was directly linked with lipid peroxidation and free radical formation in the axes and that these events taken together may contribute to loss of viability in these recalcitrant seeds.

The role of ascorbate in drought-treated Cochlearia atlantica Pobed. and Armeria maritima (Mill.) Willd.

Cochlearia atlantica is a species rich in ascorbic acid. After 4 days of intermittent drought treatment, there was a large decrease in the concentration of ascorbate and glutathione, functioning probably as radical scavengers (anti-oxidants). Although there was no increase in lipid peroxidation (a marker of oxygen radical damage), drought treatment did result in the destruction of chlorophyll and a decrease in protein. This species showed little or no change in the activities of five enzymes usually associated with the processing of, and protection from, activated forms of oxygen. Armeria maritima showed similar decreases in relative water content and dry weight after droughting, but a quantitatively smaller decrease in ascorbate with no loss of glutathione. Instead a major response to drought, in this species, was the marked increases in the activities of superoxide dismutasc and peroxidase. Despite these increases in enzymic defences against oxygen radicals, drought treatment resulted in increased lipid peroxidation. in A. maritima. It is concluded that ascorbic acid and glutathione may play a significant role in the response to drought in C. atlantica but protection in A. maritima is largely through enzymic processing of activated farms of oxygen.

THE DEGRADATION OF CHLOROPHYLL - A BIOLOGICAL ENIGMA.

Some 109 tonnes of chlorophyll are destroyed each year on land and in the oceans. The fate of these chlorophylls is, however, largely unknown. This review describes the developmental stages at which chlorophyll breakdown occurs in aquatic and terrestrial biological systems, and the destruction arising from herbivory, disease, pollution and other physical hazards. At the cellular level, an attempt is made to separate the breakdown of chlorophyll during senescence from the many other events associated with cell destruction and death. A consideration of the more important chemical and biophysical properties of chlorophylls and their derivatives is provided, together with data on their spectral properties. The biosynthetic and biodegradative pathways of chlorophyll metabolism are, so far as is possible, described with some predictions as to the likely fate of the missing tonnes. Two types of degradation are recognized; the first involves up to five defined enzymes concerned with the early stages, the second covers the less well defined enzymic and non-enzymic destruction of the macrocyclic structure. These degradative reactions are compared with the reactions implicated in the breakdown of other porphyrins including haems in plants and animals. A brief description is given of the occurrence of breakdown products of chlorophyll in past biomass, including those of geological significance and those in a more recent archaeological context. Finally, the economic significance of chlorophyll breakdown is considered in the context of agriculture and horticulture, veterinary and medical sciences, food colouring and cosmetic industries, and the multi-million-dollar attraction of autumn leaf fall to tourism. Contents Summary 256 I. Introduction 256 II. Chlorophylls: global production and destruction 259 III. Chlorophylls: nomenclature and chemical characteristics 260 IV. Chlorophyll metabolism 268 V. Chlorophyll degradation during senescence 274 VI. Other degradative conditions 278 VII. Breakdown products in past biomass 287 VIII. Pathways of degradation 289 IX. Economic importance 291 Acknowledgements 294 References 294.

IRON-INDUCED OXYGEN RADICAL METABOLISM IN WATERLOGGED PLANTS.

Roots of the iron-sensitive wetland plant, Epilobium hirsutum L., respond to oxygen-depletion by enhanced uptake of ferrous ions. Evidence is presented for an iron-catalyzed reaction within roots leading to super oxide radical formation and the induction of superoxide dismutase. The immediate product, H2 O2 , appears to accumulate in the absence of catalase and low activity of root peroxidases, resulting in hydroxyl radical formation, inhibition of protein synthesis, increased lipid peroxidation and gross cellular damage. Evidence for alternative 'healthy' responses is given. A scheme is presented which outlines a biochemical mechanism for iron-mediated flood or waterlogging tolerance and intolerance in plants.