Profiling of Silk Sericin from Cocoons of Three Southern African Wild Silk Moths with a Focus on Their Antimicrobial and Antioxidant Properties

Silk sericin was extracted from the cocoons of three Southern African wild silk moth species, namely Gonometapostica, G. rufobrunnae (Lepidoptera: Lasiocampidae), and Argema mimosae (Lepidoptera: Saturniidae); these three sericin extracts were analysed to determine the relationship that exists between their chemical structures and their functional properties. The relationship was investigated by utilising several methods that include the determination of the amino acid composition, and characterisation of the secondary structures with Fourier transformation infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The antibacterial properties of these three sericin extracts were evaluated by an agar well diffusion assay with three Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis) as test microorganisms; and, lastly, the antioxidant properties of the three sericin extracts were determined using several scavenging methods that include the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS˙⁺), and the ferric reducing antioxidant power (FRAP) assay. The amino acid composition in the silk sericin extracts from G. postica, G. rufobrunnea, and Argema mimosa in terms of the polar/non-polar ratio (P/NP) was found to be 65:35, 56:44, and 59:41, respectively. The FTIR spectra of these three silk sericin extracts showed distinct major bands such as amide A (3265 cm⁻¹), amide B (3062 cm⁻¹), amide I (1644 cm⁻¹), amide II (1538 cm⁻¹), and amide III (1244 cm⁻¹). The XRD patterns of the silk sericin extracts revealed both amorphous and α-helical structures, with small crystalline regions. All three silk sericin extracts presented potent antibacterial efficacy against the three Gram-positive bacteria and were found to have excellent antioxidant activities against the tested free radicals.     

Osteoclastic giant cell tumor of the pancreas

INTRODUCTION

Pancreatic giant cell tumors are rare, with an incidence of less than 1% of all pancreatic tumors. Osteoclastic giant cell tumor (OGCT) of the pancreas is one of the three types of PGCT, which are now classified as undifferentiated carcinoma with osteoclast-like giant cells.

PRESENTATION OF CASE

The patient is a 57 year old woman who presented with a 3 week history of epigastric pain and a palpable abdominal mass. Imaging studies revealed an 18 cm × 15 cm soft tissue mass with cystic components which involved the pancreas, stomach and spleen. Exploratory laparotomy with distal pancreatectomy, partial gastrectomy and splenectomy was performed. Histology revealed undifferentiated pancreatic carcinoma with osteoclast-like giant cells with production of osteoid and glandular elements.

DISCUSSION

OGCT of the pancreas resembles benign-appearing giant cell tumors of bone, and contain osteoclastic-like multinucleated cells and mononuclear cells. OGCTs display a less aggressive course with slow metastasis and lymph node spread compared to pancreatic adenocarcinoma. Due to the rarity of the cancer, there is a lack of prospective studies on treatment options. Surgical en-bloc resection is currently considered first line treatment. The role of adjuvant therapy with radiotherapy or chemotherapy has not been established.

CONCLUSION

Pancreatic giant cell tumors are rare pancreatic neoplasms with unique clinical and pathological characteristics. Osteoclastic giant cell tumors are the most favorable sub-type. Surgical en bloc resection is the first line treatment. Long-term follow-up of patients with these tumors is essential to compile a body of literature to help guide treatment.     

Investigation of Self-Healing Mortars with and without Bagasse Ash at Pre- and Post-Crack Times

Cracks in typical mortar constructions enhance water permeability and degrade ions into the structure, resulting in decreased mortar durability and strength. In this study, mortar samples are created that self-healed their cracks by precipitating calcium carbonate into them. Bacillus subtilus bacterium (10⁻⁷, 10⁻⁹ cells/mL), calcium lactate, fine aggregate, OPC-cement, water, and bagasse ash were used to make self-healing mortar samples. Calcium lactates were prepared from discarded eggshells and lactic acid to reduce the cost of self-healing mortars, and 5% control burnt bagasse ash was also employed as an OPC-cement alternative. In the presence of moisture, the bacterial spores in mortars become active and begin to feed the nutrient (calcium lactate). The calcium carbonate precipitates and plugs the fracture. Our experimental results demonstrated that cracks in self-healing mortars containing bagasse ash were largely healed after 3 days of curing, but this did not occur in conventional mortar samples. Cracks up to 0.6 mm in self-healing mortars were filled with calcite using 10⁻⁷ and 10⁻⁹ cell/mL bacteria concentrations. Images from an optical microscope, X-ray Diffraction (XRD), and a scanning electron microscope (SEM) were used to confirm the production of calcite in fractures. Furthermore, throughout the pre- and post-crack-development stages, self-healing mortars have higher compressive strength than conventional mortars. The precipitated calcium carbonates were primed to compact the samples by filling the void spaces in hardened mortar samples. When fissures developed in hardened mortars, bacteria became active in the presence of moisture, causing calcite to precipitate and fill the cracks. The compressive strength and flexural strength of self-healing mortar samples are higher than conventional mortars before cracks develop in the samples. After the healing process of the broken mortar parts (due to cracking), self-healing mortars containing 5% bagasse ash withstand a certain load and have greater flexural strength (100 kPa) than conventional mortars (zero kPa) at 28 days of cure. Self-healing mortars absorb less water than typical mortar samples. Mortar samples containing 10⁻⁷ bacteria cells/mL exhibit greater compressive strength, flexural strength, and self-healing ability. XRD and SEM were used to analyze mortar samples with healed fractures. XRD, FTIR, and SEM images were also used to validate the produced calcium lactate. Furthermore, the durability of mortars was evaluated using DTA-TGA analysis and water absorption tests.     

Predictors of subjective recovery from recent-onset psychosis in a developing country: a mixed-methods study

Purpose

This study was conducted to: (a) investigate the levels and progress of subjective recovery from recent-onset psychosis; (b) examine its predictive factors and; (c) describe perceived challenges and opportunities affecting recovery. The findings were expected to help inform recovery-oriented psychiatric care in low-income, particularly African, countries.

Methods

This sequential explanatory mixed-methods study involved 263 service users with recent-onset psychosis from Northwestern Ethiopia. For the quantitative part, a 9-month longitudinal study approach was employed with three time point measurements over 9 months. Predictor variables for subjective recovery from recent-onset psychosis were identified by hierarchical multiple linear regression tests. Following the quantitative survey, individual qualitative interviews were conducted with 19 participants. Interview data were transcribed and thematically analysed.

Results

High mean subjective recovery scores were recorded throughout the study (Questionnaire about the Process of Recovery score ranging from 44.17 to 44.65). Quality of life, internalized stigma, disability, hopelessness, satisfaction with social support, and central obesity were significant predictors of subjective recovery across the three time points. Participants’ perceived challenges and opportunities affecting their recovery were categorized into four themes.

Conclusion

In Ethiopia, a low percentage of individuals with SMIs initiate psychiatric treatment and many discontinue this to attend spiritual healing. In this study, the Ethiopian SMI patients engaged consistently in psychiatric treatment indicated high mean subjective recovery scores. Devising mechanisms to integrate the psychiatric treatment and spiritual healing sectors are suggested. Approaches to improve quality of life, functioning, hope, internalized stigma and provide need-based social support are suggested.

     

Initial antiretroviral therapy in chronically-infected HIV-positive adults

Currently, there are 20 individual antiretroviral drugs and two co-formulation products that are approved by the FDA for the treatment of HIV-infected individuals. It is widely accepted that the selection of an appropriate first-line regimen is critical in assuring durable treatment response. This article reviews the factors that should be considered in the selection of an initial antiretroviral regimen and present the currently available evidence regarding the status of individual antiretroviral agents and treatment strategies relative to these factors.     

Emerging concepts in disease management: a role for antimicrobial therapy in coronary artery disease

Coronary artery disease, the leading cause of morbidity and mortality in developed countries, is a chronic inflammatory process that develops in response to a variety of injuries. A number of microbial organisms have been implicated in its pathogenesis. The strongest evidence to date for an association between an infectious agent and coronary heart disease is that for Chlamydia pneumoniae. Evidence implicating other microbial organisms is much less compelling. Sero-epidemiological and pathological data have linked infection with C. pneumoniae to atherosclerotic coronary artery disease. A possible mechanism by which C. pneumoniae may participate in the pathogenesis of atherosclerosis is through immune activation and the initiation of a chronic inflammatory state in the infected arterial wall. Locally secreted inflammatory cytokines trigger a cascade of secondary cellular processes that lead to characteristic structural changes. C. pneumoniae has been detected in atherosclerotic plaques and in the serum of patients with coronary artery disease. It induces foam cells (the hallmark of early atherosclerosis) and it markedly accelerates this disease process in animal models. C. pneumoniae has been associated with elevated levels of inflammatory cytokines and acute phase reactants. Data from three interventional studies in humans have suggested that treatment with antibiotics decreases inflammatory markers and perhaps influences the anti-C. pneumoniae antibody titers; however, adverse clinical events were not uniformly reduced in all trials. Two large prospective clinical trials, the WIZARD trial and ACES, are underway to confirm these preliminary findings and test the hypothesis that antibiotics may be beneficial in preventing or modifying the course of coronary artery disease. At present, antimicrobial therapy for atherosclerosis is not advocated outside of well-controlled research settings.     

Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation

In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land–atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.

During the past 50 y, ∼20% of the Amazon forest has been lost to deforestation (1, 2). These changes in the land surface have affected the functioning of ecosystems and the climate in ways we are only starting to understand. Deforestation size, for instance, is a potential factor defining the magnitude and characteristics of changes in local climate associated with forest loss (3, 4). There is also evidence that the different land uses that follow deforestation can regulate the magnitude of changes in surface energy balance and water cycle (5). Historically, there has been large variation in the characteristics and causes of deforestation (1, 6–9). In the area known as the “arc of deforestation,” two major processes have contributed to forest loss: government-supported rural settlements and expansion of market-focused large-scale agriculture (hereinafter referred to as “commodity agriculture”) (10, 11). Deforestation caused by these two types of farming systems has distinct characteristics, and each can have several variants.Rural settlements are generally associated with government colonization projects, migratory flow incentives, and the construction of new roads (7). In areas dominated by rural settlements, small properties with plots ranging from 25 to 100 ha are predominant (8, 9, 12). However, medium-sized properties ranging from 250 to 1,000 ha and farms larger than 1,000 ha may also occur. Activities inside these areas are characterized by livestock production (extensive pastures), small-scale crop production, and family farming (13). The establishment of small farms along main highways and secondary roads results in the well-known “fish bone” deforestation pattern.Forest areas taken by large-scale commodity agriculture represent a more recent stage of occupation, usually associated with spontaneous and economical migration but also, with changes in land use policies and market conditions (14). Agricultural activities aimed at commodity crop plantation are in general productive and often technologically advanced. The most common commodity crops in the Amazon region are soybean, maize, sorghum, and cotton. Nonetheless, forests are typically not converted directly into croplands, with pastures often used as a transitory land use. Permanent mid- to large-scale cattle ranching also occurs, although many of these areas are being rapidly converted into croplands (6, 14–16). Farm sizes can reach several thousand hectares. Properties are, therefore, bigger and more isolated, in comparison with rural settlements (13).Given the different characteristics of commodity agriculture and rural settlements, the spatiotemporal patterns of land cover biophysical properties can also differ considerably. In general, commodity crops cultivation involves an intensive use of the land, sometimes with two or more harvests per year (17). Hence, rapid changes in the vegetation cover, albedo, and evapotranspiration (ET) can occur (5, 18). On the other hand, in areas where small-scale pastures and agriculture are prevalent, the biophysical properties of the land surface are expected to vary less, given the less intensive use of the land (e.g., associated with family farming and agroforestry). Furthermore, modeling studies suggest that the type of vegetation involved in land cover conversions is important in determining the sign of the land change impacts (19). However, empirical studies are crucially needed to better understand how different land uses across the Amazon region affect the local and regional climate.Tropical deforestation has deep impacts on biophysical processes (1, 20–22), contributing to amplifying diurnal temperature variability (1.95 ± 0.08 °C) as well as increasing mean air temperature (∼1 °C) (23). The causes of increase in temperature are dominated by nonradiative mechanisms, in particular a decrease in latent heat flux (LE) (24). The cooling effects of albedo increase due to deforestation are in most cases outweighed by the warming effects of decreasing ET, leading to net warming (23–25).The impacts of Amazon deforestation on rainfall patterns are not yet fully understood (4). In the initial phases of deforestation, vegetation loss was shown to increase regional cloudiness and precipitation (3). In comparison with deforested areas, the greater humidity over forests leads to more convective available potential energy, which makes the atmospheric boundary layer more unstable (26). Conversely, small deforestation patches showed more active shallow convection, explaining the higher frequency of shallow clouds over deforested areas (26). However, it is unclear how these mechanisms change as deforested areas increase and land cover becomes more uniform. One hypothesis is that convective lifting mechanisms will lose force, and shallow clouds over deforested areas will no longer be favored. Modeling studies indicate that this shift is already happening in some parts of the Amazon, where deforestation has reached a point in which thermally dominated regime has declined, leading to a more dynamically driven hydroclimatic regime (27). A dynamically driven regime becomes dominant when differences in surface roughness between forest and forest clearings start to play a larger role in the atmospheric response, in comparison with the differences in the surface energy partitioning (28).As observational and modeling studies indicate that land use and management can play an important role in the climate system, overlooking these landscape heterogeneities can hinder an adequate response to the threats posed by human activities (29). Clarifying the climatic impacts of different land uses in the Amazon is crucial to foster informed plans for sustainable land management, in particular those aiming at strategies for climate change mitigation, maintenance of ecological functioning, and guarantying provision of essential ecosystem services. Here, we hypothesize that forest conversion to large-scale commodity agriculture is more detrimental to local climate than conversion to rural settlements. To test this hypothesis, we first evaluated whether or not land uses associated with commodity agriculture and rural settlements lead to quantitatively distinguishable land cover spatiotemporal patterns in regions with similar deforestation rates (1985 to 2018) and total deforested area in 2018. Next, we collected empirical evidence on how forest clearing associated with these two causes has affected local rainfall, surface temperature, and LE.     

The latest in antiretroviral therapy

The XVI International AIDS Conference (AIDS 2006), organized by the International AIDS Society (IAS), took place August 12-18 in Toronto, Canada. It was attended by over 26,000 participants from more than 170 countries and featured more than 4,500 abstracts as well as an array of community and cultural activities. The theme of the meeting was "Time to deliver", emphasizing the continued need and urgency in bringing effective HIV prevention and treatment strategies to those living with and affected by HIV/AIDS. The meeting's agenda was broad and included policy and programmatic topics as well as scientific research. This report focuses on reports presented at the conference that directly deal with antiretroviral therapy. This is primarily because of the nature of the venue where it is intended to be published (Drug News & Perspectives) as well as the expertise of the author. It is not a lack of recognition of the other equally important topics and discussions that took place at AIDS 2006. The author is solely responsible for the selection of topics and presentations to be included in this report.     

cIAP1 Localizes to the nuclear compartment and modulates the cell cycle

We explored the location and function of the human cIAP1 protein, a member of the inhibitor of apoptosis protein (IAP) family. Unlike family member X-linked IAP (XIAP), which was predominantly cytoplasmic, the cIAP1 protein localized almost exclusively to nuclei in cells, as determined by immunofluorescence microscopy and subcellular fractionation methods. Interestingly, apoptotic stimuli induced nuclear export of cIAP1, which was blocked by a chemical caspase inhibitor. In dividing cells, cIAP1 was released into the cytosol early in mitosis, then reaccumulated in nuclei in late anaphase and in telophase, with the exception of a pool of cIAP1 that associated with the midbody. Survivin, another IAP family member, and cIAP1 were both localized on midbody microtubules at telophase, and also interacted with each other during mitosis. Cells stably overexpressing cIAP1 accumulated in G(2)-M phase and grew slower than control-transfected cells. These cIAP1-overexpressing cells also exhibited cytokinesis defects over 10 times more often than control cells and displayed a mitotic checkpoint abnormality with production of polyploid cells when exposed to microtubule-targeting drugs nocodazole and paclitaxel (Taxol). Our findings demonstrate a role for overexpressed cIAP1 in genetic instability, possibly by interfering with mitotic functions of Survivin. These findings may have important implications for cancers in which cIAP1 overexpression occurs.