The effect of lactose-conjugated silk biomaterials on the development of fibrogenic fibroblasts

Surface properties of implanted biomaterials can cause fibrotic tissue reactions by stimulating differentiation of host fibroblasts into contractile myofibroblasts. Silk fibroin (SF) protein has been used as biomaterial in pure and blended form. however, its effect on myofibroblast differentiation remains elusive. We here conjugated SF with lactose using cyanuric chloride as coupling spacer. NMR spectroscopy and the conjugates ability to agglomerate Abrus precatorius agglutinin verified efficient conjugation. Two-dimensional films and three-dimensional scaffolds produced from pure and lactose-conjugated SF solutions were tested as culture substrates for subcutaneous fibroblasts and myofibroblasts. Lactose-conjugated SF substrates mediated higher adhesion, proliferation and viability of fibroblastic cells than pure SF. This SF film composition promotes better attachment of fibroblasts than myofibroblasts. Pro-fibrotic cytokine TGFbeta1 was ineffective in inducing fibroblast-to-myofibroblast differentiation on such substrates. Pre-differentiated myofibroblasts lost their contractile phenotype within a few days of being cultured on lactose-conjugated SF. Myofibroblast differentiation was also suppressed by growth in three-dimensional lactose-conjugated SF scaffolds that, however, support population with fibroblasts. We propose that this biomaterial will promote tissue integration without causing a fibrotic host reaction.     

Potential of biocompatible regenerated silk fibroin/sodium N-lauroyl sarcosinate hydrogels

Hydrogels are becoming widely used in biomaterial applications. The available methods for the preparation of these materials are continually growing. The gelation time (GT) of silk protein fibroin is difficult to control by physical methods. The cross-linkers used in available chemical techniques are likely to impact the biocompatibility of the resultant materials. In this paper, we demonstrate that the addition of sodium N-lauroyl sarcosinate (an amino-acid-based surfactant) accelerates the formation of hydrogels from fibroin. GT, turbidity variations, changes of viscoelasticity during the gelation process, and the mechanical properties of the products are measured. The secondary structure was probed by Fourier transform infrared spectroscopy, X-ray diffraction and the morphologies of the products were investigated by scanning electron microscopy. Transformations in the β-sheet content were monitored by the fluorescence of Thioflavine T and circular dichroism measurements. The relationship between the surface tension of sodium N-lauroyl sarcosinate and the GT was also explained. To investigate cell compatibility, fibroblast cells were seeded onto the surface of the hydrogels. The results indicate that the sodium N-lauroyl sarcosinate/fibroin GT can be controlled. This blend-hydrogel demonstrates excellent cell compatibility, good compression strength, and outstanding compression-recovery characteristics. Sodium N-lauroyl sarcosinate/silk fibroin hydrogels containing β-sheets have considerable potential as replacement materials in addressing the tissue defects involved with repair surgery.     

Nucleotide sequence and genome organization of Dweet mottle virus and its relationship to members of the family Betaflexiviridae

The nucleotide sequence of Dweet mottle virus (DMV) was determined and compared to sequences of members of the families Alphaflexiviridae and Betaflexiviridae. The DMV genome has 8,747 nucleotides (nt) excluding the 3′ poly-(A) tail. DMV genomic RNA contains three putative open reading frames (ORFs) and untranslated regions of 73 nt at the 5′ and 541 nt at 3′ termini. ORF1 potentially encoding a 227.48-kDa polyprotein, which has methyltransferase, oxygenase, endopeptidase, helicase, and RNA-dependent RNA polymerase (RdRP) domains. ORF2 encodes a movement protein of 40.25 kDa, while ORF3 encodes a coat protein of 40.69 kDa. Protein database searches showed 98–99% matches of DMV ORFs with citrus leaf blotch virus (CLBV) sequences. Phylogenetic analysis based on the RdRP core domain revealed that DMV is closely related to CLBV as a member of the genus Citrivirus. DMV did not satisfy the molecular criteria for demarcation of an independent species within the genus Citrivirus, family Betaflexiviridae, and hence, DMV can be considered a CLBV isolate.     

Association of LAR-like receptor protein tyrosine phosphatases with an enabled homolog in Hirudo medicinalis

Receptor protein tyrosine phosphatases (RPTPs) are thought to play important functions in pathfinding and target recognition by growing neuronal processes. The leech RPTPs HmLAR1 and HmLAR2 are expressed selectively by central neurons, Comb cells, and peripheral muscle tissues in the Hirudo medicinalis embryo. To explore the functions of HmLARs, we have sought to determine their physiological substrates. We report here the cloning and embryonic expression of Lena, the leech homolog of Enabled, a cytosolic protein implicated in actin-based cell motility. Lena is expressed in embryonic central neurons and in the Comb cell. We present experimental evidences indicating that Lena associates selectively with the intracellular domain of HmLAR1 and HmLAR2. Additionally, RNA interference (RNAi) of HmLAR1 in intact leech embryos leads to the hyperphosphorylation of Lena. We propose, therefore, that Lena is an in vivo substrate of HmLAR1 in neurons and perhaps of HmLAR2 in the Comb cells.     

Unsafe abortion: a neglected tragedy. Review from a tertiary care hospital in India

AIM: With 16% of the world's population, India accounts for over 20% of the world's maternal deaths. The maternal mortality ratio, defined as the number of maternal deaths per 100 000 live births is incredibly high at 408 per 100 000 live births for the country. Abortion has been legalized in India for the past three decades. However, the share of unsafe abortion as a cause of maternal mortality continues to be alarming. The objective of the present study is to identify the magnitude of problem of unsafe abortion in India. METHODS: Emergency gynecologic admissions to a tertiary care center in North India over a 15-year period (1988-2002) were reviewed to evaluate the demographic and clinical profile of patients admitted as a result of unsafe abortion. The records were analyzed with regard to the age group, parity and marital status of the abortion seekers, the indication of abortion, the methods used, qualification of abortion providers, complications and fatality rate. RESULTS: The majority of women who were admitted with diagnosis of unsafe abortion were in the third decade of their lives. They were married, multiparous women living with their spouses. Sixty percent of the women had approached unqualified abortion providers who used primitive methods of pregnancy termination. All the women were admitted with serious complications of unsafe abortions and one-fourth of them succumbed to the complications. CONCLUSION: Unsafe abortion constitutes a major threat to the health and lives of women. This study highlights the need to focus more directly on the needs and preferences of women who seek abortion as well as on the accessibility of contraceptives and skills of the providers of abortion services, in order to improve the quality of abortion care.     

Guidelines for managing pressure ulcers with negative pressure wound therapy

Pressure ulcers are a serious health issue, leading to clinical, financial, and emotional challenges. Numerous treatment modalities are available to promote wound healing, yet clinicians may be unsure how to incorporate these treatment options into an overall plan of care for the patient with a pressure ulcer. A consensus panel of experienced wound care clinicians convened in July 2004 to review the mechanisms of action and research basis for one such treatment modality: negative pressure wound therapy. After answering key questions about this modality, they developed an algorithm to assist the clinician in making decisions about using negative pressure wound therapy appropriately in patients with Stage III and Stage IV pressure ulcers.     

Platelet-activating factor activates mitogen-activated protein kinases,inhibits proliferation,induces differentiation and suppresses the malignant phenotype of human colon carcinoma cells

Recent studies suggest that the action of platelet-activating factor (PAF), a potent phospholipid modulator of allergic and inflammatory reactions, is diverse and functions as a modulator of a variety of physiological and pathological events in many cell types and tissues. Its role (if any) in modulating the proliferation, transformation and/or differentiation of epithelial colonic cells, however, is not known. In this study, we showed that PAF is biologically active in epithelial-derived human colon carcinoma cells with different phenotypic properties. These cells expressed the PAF receptor. PAF activated three prominent mitogen-activated protein kinase modules (ERK, p38MAPK and Jun N-terminal kinases) in these cells, inhibited proliferation and induced differentiation (measured by the induction of Waf1/p21 and the induction of the differentiation-related marker CEA). The net effect of PAF treatment was the suppression of malignant cell behavior (measured by anchorage-independent growth and cellular invasion). It is concluded that PAF is a modulator of proliferation and differentiation in human epithelial-derived colon carcinoma cells.     

Hyponatremia in critically ill patients

Context:

Hyponatremia is a common electrolyte disturbance in critically ill hence understanding its implications is important.

Aims:

This study was carried out to ascertain frequency, predisposing conditions and outcome in critically ill patients with hyponatremia on intensive care unit (ICU) admission.

Settings and Design:

This was an observational, prospective study of a series of ICU patients during a 12-month period.

Materials and Methods:

The patients were divided into two groups: Hyponatremic (serum sodium < 135 mmol/L) and Eunatremic groups (135-145 mmol/L). Clinical examination included volume status and drug history, biochemistries, clinical diagnosis and cause of hyponatremia.

Statistical Analysis Used:

Fisher''s exact test, unpaired t-tests Wilcoxon ranksum tests, profile-likelihood method, log-rank test and Kaplan—Meier curves were used. P < 0.05 were considered to be statistically significant.

Results:

In the hyponatremic group, the frequency of hyponatremia on ICU admission was 34.3%, most were euvolumic, 58.96%. Females comprised of 36.5%. The mean age was 60.4 ± 17.2. The Syndrome of inappropriate Antidiuretic Hormone (SIADH) criteria was met in ninety-one patients (36.25%), peumonia being the leading cause of SIADH. Patients with severe sepsis, elective surgery patients, renal failure and heart failure, cirrhosis of liver and subarachnoid hemorrhage were other more likely etiologic causes (P < 0.05). The hyponatremic group spent a longer time in the ICU (P = 0.02), had longer mechanical ventilator days (P < 0.05) and had an increased mortality rate (P = 0.01).

Conclusions:

Hyponatremia present on admission to the ICU is independent risk factors for poor prognosis.     

Assessment of Total Mercury Level in Fish Collected from East Calcutta Wetlands and Titagarh Sewage Fed Aquaculture in West Bengal, India

Total mercury levels were quantified in Tilapia mossambicus, Cirrhinus mrigela and Labio rohita, captured from East Calcutta Wetlands and Titagarh sewage fed aquaculture ponds. The bioconcentration factor of collected fish was assessed. Total mercury level ranged from 0.073 to 0.94 μg/g in both pre and post monsoon season. T. mossambicus in both season and C. mrigela at pre monsoon, cross the Indian recommended maximum limit (0.50 μg/g wet weight) for food consumption and according to World Health Organization guidelines all fish were not recommended for pregnant women and individuals under 15 years ages. A significant correlation was observed between mercury content of aquaculture pond water and fish muscle tissue. Total mercury concentration in experimental sites were higher than the control area (Wilcoxon Ranked-Sum test p > 0.05), which suggested the connection between mercury bioaccumulation and sewage fed aquaculture.