Studi Ketoksikan Dinoflagelata Spesies Prorocentrum Minimum (Dinophyceae) Schiller (Pavillard)

This study was carried out to determine the toxicity of the dinoflagellate Prorocentrum minimum species that formed massive blooms in Lido Beach, Johor Bahru in July 2002. Clone cultures were established in ES-DK medium at 26o C under a 14:10 hour light dark cycle. Species toxicity was determined by intra peritoneal (i.p) injection of culture extract into mice. Cultured cell extracts were toxic to mice. The major symptoms were muscular paralysis and diarrhea. However no mouse mortality was observed even after 13 hours. Extracts of cultured cells were also hemolytic on rabbit red blood cells. Keywords: Dinoflagellate, HAB, Prorocentrum minimum, Red Tide dan Toxicity Kajian dilakukan untuk menentukan ketoksikan dinoflagelata spesies Prorocentrum minimum yang menyebabkan kejadian pasang merah besar-besaran di perairan Pantai Lido, Johor Bahru pada Juli tahun 2002. Kultur klon telah dibuat dalam medium ES-DK pada suhu 26o C dan siklus pencahayaan 14:10 jam terang gelap. Ketoksikan spesies diuji dengan penyuntikan ekstrak kultur secara intra peritoneal (i

The Book of Opposites: The Role of the Nuclear Receptor Co-regulators in the Suppression of Epidermal Genes by Retinoic Acid and Thyroid Hormone Receptors

Transcriptional regulation by nuclear receptors occurs through complex interactions that involve DNA response elements, co-activators/co-repressors, and histone modifying enzymes. Very little is known about how molecular interplay of these components may determine tissue specificity of hormone action. We have shown previously that retinoic acid (RA) and thyroid hormone (T3) repress transcription of a specific group of epidermal keratin genes through a novel mechanism that utilizes receptors homodimers. In this paper, we have analyzed the epidermal specificity of RA/T3 action by testing the role of co-repressors and co-activators in regulation of epidermal genes. Using transient co-transfections, northern blots, antisense oligonucleotides, and a histone deacetylase (HDAC) inhibitor, trichostatin A, we found that in the context of specific keratin RE (KRE), co-activators and histone acetylase become co-repressors of the RA/T3 receptors in the presence of their respective ligands. Conversely, co-repressors and HDAC become co-activators of unliganded T3Rα. The receptor–co-activator interaction is intact and occurs through the NR-box. Therefore, the role of co-activator is to associate with liganded receptors whereas the KRE–receptor interaction determines specific transcriptional signal, in this case repression. This novel molecular mechanism of transcriptional repression conveys how RA and T3 target specific groups of epidermal genes, thus exerting intrinsic tissue specificity

Primary cultured fibroblasts derived from patients with chronic wounds: a methodology to produce human cell lines and test putative growth factor therapy such as GMCSF

<p>Abstract</p> <p>Background</p> <p>Multiple physiologic impairments are responsible for chronic wounds. A cell line grown which retains its phenotype from patient wounds would provide means of testing new therapies. Clinical information on patients from whom cells were grown can provide insights into mechanisms of specific disease such as diabetes or biological processes such as aging.</p> <p>The objective of this study was 1) To culture human cells derived from patients with chronic wounds and to test the effects of putative therapies, Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) on these cells. 2) To describe a methodology to create fibroblast cell lines from patients with chronic wounds.</p> <p>Methods</p> <p>Patient biopsies were obtained from 3 distinct locations on venous ulcers. Fibroblasts derived from different wound locations were tested for their migration capacities without stimulators and in response to GM-CSF. Another portion of the patient biopsy was used to develop primary fibroblast cultures after rigorous passage and antimicrobial testing.</p> <p>Results</p> <p>Fibroblasts from the non-healing edge had almost no migration capacity, wound base fibroblasts were intermediate, and fibroblasts derived from the healing edge had a capacity to migrate similar to healthy, normal, primary dermal fibroblasts. Non-healing edge fibroblasts did not respond to GM-CSF. Six fibroblast cell lines are currently available at the National Institute on Aging (NIA) Cell Repository.</p> <p>Conclusion</p> <p>We conclude that primary cells from chronic ulcers can be established in culture and that they maintain their <it>in vivo </it>phenotype. These cells can be utilized for evaluating the effects of wound healing stimulators <it>in vitro</it>.</p

Innate immunity and microbial dysbiosis in hidradenitis suppurativa – vicious cycle of chronic inflammation

Hidradenitis Suppurativa (HS) is a chronic multifactorial inflammatory skin disease with incompletely understood mechanisms of disease pathology. HS is characterized by aberrant activation of the innate immune system, resulting in activation of pathways that aim to protect against pathogenic microorganisms, and also contribute to failure to resolve inflammation. Imbalance in innate immunity is evident in deregulation of host antimicrobial peptides (AMPs) and the complement system associated with the microbiome dysbiosis. The pathology is further complicated by ability of pathogens associated with HS to overcome host immune response. Potential roles of major AMPs, cathelicidin, defensins, dermcidin, S100 proteins, RNAse 7 and complement proteins are discussed. Dysregulated expression pattern of innate immunity components in conjunction with bacterial component of the disease warrants consideration of novel treatment approaches targeting both host immunity and pathogenic microbiome in HS

Nuclear Proteins Involved in Transcription of the Human K5 Keratin Gene

Keratin K5 is expressed in the basal layer of stratified epithelia in mammals and its synthesis is regulated by hormones and vitamins such as retinoic acid. The molecular mechanisms that regulate K5 expression are not known. To initiate analysis of the protein factors that interact with the human K5 keratin gene upstream region, we have used gel-retardation and DNA-mediated cell-transfection assays. We found five DNA sites that specifically bind nuclear proteins. DNA-protein interactions at two of the sites apparently increase transcription levels, at one decrease it. The importance of the remaining two sites is, at present, unclear. In addition, the location of the retinoic acid and thyroid hormone nuclear receptor action site has been determined, and we suggest that it involves a cluster of five sites similar to the consensus recognition elements. The complex constellation of protein binding sites upstream from the K5 gene probably reflects the complex regulatory circuits that govern the expression of the K5 keratin in mammalian tissues

Angiogenin released from ABCB5+ stromal precursors improves healing of diabetic wounds by promoting angiogenesis

Severe angiopathy is a major driver for diabetes-associated secondary complications. Knowledge on the underlying mechanisms essential for advanced therapies to attenuate these pathologies is limited. Injection of ABCB5+ stromal precursors at the edge of nonhealing diabetic wounds in a murine db/db model, closely mirroring human type 2 diabetes, profoundly accelerates wound closure. Strikingly, enhanced angiogenesis was substantially enforced by the release of the ribonuclease angiogenin from ABCB5+ stromal precursors. This compensates for the profoundly reduced angiogenin expression in nontreated murine chronic diabetic wounds. Silencing of angiogenin in ABCB5+ stromal precursors before injection significantly reduced angiogenesis and delayed wound closure in diabetic db/db mice, implying an unprecedented key role for angiogenin in tissue regeneration in diabetes. These data hold significant promise for further refining stromal precursors–based therapies of nonhealing diabetic foot ulcers and other pathologies with impaired angiogenesis

Gene array technology and pathogenesis of chronic wounds

Many of the limitations in treatment of chronic wounds are based on lack of knowledge of the molecular mechanism(s) of wound healing. Furthermore, diagnostic tools in wound healing are still primarily macroscopic, visual, and histologic. Thus, by understanding mechanisms of wound healing at a molecular level, new treatments can be designed, prevention programs developed, and a better understanding of current treatments provided. The ability to methodically analyze the expression patterns of thousands of genes simultaneously allows for identification of groups of molecular defects that lead to chronic inhibition of the wound-healing process. Gene array technology is having a major impact on the field of wound healing and has the potential to profoundly affect the way we understand the pathogenesis, diagnosis, prevention, and treatment of chronic wounds. Currently, gene array technology is used in the field of chronic wound healing to (1) understand the pathogenesis of pressure ulcers and venous ulcers, (2) understand the pathogenesis of diabetic foot ulcers, including the role that neuropathy may play in delayed healing of diabetic foot ulcers, and (3) determine the mechanism(s) of established and new local treatments, that is, pharmacogenomics for pressure ulcers and diabetic foot ulcers

Healing Chronic Wounds: Current Challenges and Potential Solutions

The purpose of this review is to raise awareness, examine the challenges faced by wound care researchers, and explore opportunities for potential improvements.Chronic wounds are associated with significant morbidity and mortality, and they represent a major medical and financial burden. Despite this, no new therapy has received FDA efficacy approval for the treatment of chronic wounds since 1997. Previous preclinical studies using animal models did not translate to human wounds due to inherent limitations of experimental models, variability in assessment methods, and overall experimental design. Clinical trials continued to be challenged by the balance of the inclusion and exclusion criteria, the high cost and time expenditure of the trials, and the constraint of a single FDA-acceptable outcome of complete wound closure.Wound research faces multiple challenges in both preclinical and clinical research that slowed progress and development of efficacious therapies. Solutions to such challenges will provide new opportunities for improved study design in the future