A histological and immunohistochemical study of the effects of N-acetyl cysteine on retinopathy of prematurity by modifying insulin-like growth factor-1

Retinopathy of prematurity (ROP) is a vasoproliferative disorder that occurs in premature infants and may lead to permanent visual impairment. We investigated both the possible protective role of N-acetyl cysteine (NAC) for preventing ROP and the role of IGF-1 in the disorder. Forty-five newborn rats were divided into three groups. Group 1 was raised in room air as controls. Group 2 was exposed to 60% oxygen for 14 days after birth, then transferred to room air. Group 3 was exposed to the same conditions as group 2, but received intraperitoneal injections of NAC on postnatal days 7–17. After 35 days, both eyes of all rats were processed for histology. Some sections were stained with hematoxylin and eosin to assess structural changes and other sections were immunostained to determine the location of IGF-1. Frozen sections also were prepared and stained for adenosine triphosphatase to detect retinal blood vessels. Compared to the controls, more blood vessels, many of which were abnormal, and increased IGF-1 expression were observed in group 2. In group 3, abnormal blood vessels and IGF-1 expression were less evident. NAC appeared to be an effective vascular-protective agent for ROP by decreasing IGF-1 expression.     

The growth,reproductive phenology,and longevity of non-tide-pool Fucus distichus (L.) powell in New England

The growth, reproductive phenology, and longevity of in situ populations of Fucus distichus L. ssp. edentatus (De la Pylaie) Powell and F. distichus L. ssp. evanescens (C. Agardh) Powell were evaluated in New England. Both subspecies exhibited maximum growth during early summer, a slight decline in late summer, and a brief resurgence in the early fall. The maximum growth rates (in terms of elongation) for F. distichus ssp. edentatus and ssp. evanescens were 3.5 and 3.7 cm/28 days, respectively. Populations of both subspecies showed a distinct bimodal reproductive periodicity, with maxima in the spring and fall. Even so, individuals were either reproductive in the spring or fall but never in both seasons. After reproduction, receptacles dehisced and plants either became vegetative or died. Higher rates of plant attrition were observed during periods of reproduction than during non-reproductive periods.     

The interaction of calcium and magnesium ions with deoxyribonucleic acid.

Conductance and equilibrium dialysis studies are reported for the aqueous systems (native calf thymus) DNA-CaCl₂ and DNA-MgCl₂ at various pH values and ionic strengths at 25 °C. Discontinuities occur in the conductance curves at mole ratios of Ca²⁺ and Mg²⁺ to nucleate phosphorus of 0.125, 0.30, and 0.50. The dialysis results show the formation of complexes of stoichiometry 0.50 and 1.00 mol Ca²⁺ or Mg²⁺/mol nucleate phosphorus (2:1 and 1:1 complexes), the latter only in neutral or alkaline solutions, in agreement with the conductance discontinuity at 0.50. The other discontinuities may be due to preferential binding in the formation of the 2:1 complex. Binding constants for the 2:1 complexes are evaluated. Absorption-temperature profiles have been determined for “native” and dialysed DNA in the presence of NaCl, CaCl₂, and MgCl₂. For dialysed DNA at 26 ° C and 260 nm the decrease of absorbance with increased salt concentration was halted for MgCl₂ and CaCl₂ at a concentration corresponding to the formation of the 2:1 complex. The absorbance of “native” DNA did not decrease. T_m and the reciprocal of the hypochromic rise ($\text{1}\text{h}$) increased linearly with log (salt concn). Values of T_m were the same at 230, 260, and 280 nm, but h was greater at 230 and 280 than at 260 nm, which may be due to the existence of alternating blocks of (A + T) and (G ? C) pairs. The entropy of transition was in the order Ca > Mg ? Na.     

The taxonomic implications of genetic and environmentally induced variations in seaweed morphology

Morphological characters are the most widely used criteria for the discrimination of seaweed taxa. Even so, many examples of extreme phenotypic plasticity are known. Thus, several phycologists have recently initiated studies to evaluate the phenotypic range of taxa under varied conditions as well as to explore the degree of genetic control of individual characters. Several experimental techniques have been employed to enumerate the significance and basis of phenotypic plasticity in seaweeds, including culture studies, detailed seasonal observations of in situ populations, reciprocal transplantation of plants to diverse habitats, statistical analysis of character variations, and evaluation of genetic affinities. Obviously, the taxonomic status of seaweeds should reflect their genetic relationships. Three primary approaches are outlined including electrophoretic studies, quantitative genetic evaluations, and hybridization studies. A detailed summary of these genetic studies, as well as the other experimental field and laboratory techniques, is given in order to critically assess traditional taxonomic criteria and to aid in the search for new ones. An evaluation of the relative merits of morphological and biochemical characters in species delimitations is also outlined. It is suggested that there should be no tacit assumption that biochemical features are in some way more fundamental than morphological ones. Thus, even seemingly trivial morphological features may be of great adaptive value, even though not apparent to the taxonomist. A good taxonomic character is constant, readily observable, and the plant should survive identification. If obscure characters are used to delimit species, strenuous efforts should be made to correlate these characters with more readily observable ones.     

Recombination between kappa chain genetic markers in the mouse

In this study we report the first instance of recombination between kappa chain genetic markers in the mouse. The recombination frequency, 0.45% (95% limits, 0.12–1.61), is similar to that previously found for recombination between the kappa chain locus and the Lyt-2, 3 locus (0.3%, 95% limits, 0.05–1.6), but is relatively low in comparison with that found at the heavy chain locus (0.41–5.4%). Lyt-2, 3-typing of the recombinants permits a partial ordering of the kappa chain and Lyt-2, 3 loci as (Lyt-2, 3, Igk-Ef1) - Igk-Ef2. Light chains controlled by the two kappa markers include the V_k-(ser) subgroup (controlled by Igk-Ef1) and V_k–1 (controlled by Igk-Ef2). One of the recombinants has been recovered in a homozygous state (NAK) and should be suitable for V _k gene mapping studies.Abbreviations C complement - C_H constant region of the Ig heavy chain - CI cytotoxicity index - DNP dinitrophenyl - FMF flow microfluorimetry - IEF isoelectric focusing - IF immunofluorescence - Ig immunoglobulin - KLH keyhole limpet hemocyanin - V_H variable region of the Ig heavy chain - V_k variable region of the Ig kappa chain - V-region variable region     

Glycomics analysis of Schistosoma mansoni egg and cercarial secretions

The parasitic helminth Schistosoma mansoni is a major public health concern in many developing countries. Glycoconjugates, and in particular the carbohydrate component of these products, represent the main immunogenic challenge to the host and could therefore represent one of the crucial determinants for successful parasite establishment. Here we report a comparative glycomics analysis of the N- and O-glycans derived from glycoproteins present in S. mansoni egg (egg-secreted protein) and cercarial (0-3-h released protein) secretions by a combination of mass spectrometric techniques. Our results show that S. mansoni secrete glycoproteins with glycosylation patterns that are complex and stage-specific. Cercarial stage secretions were dominated by N-glycans that were core-xylosylated, whereas N-glycans from egg secretions were predominantly core-difucosylated. O-Glycan core structures from cercarial secretions primarily consisted of the core sequence Galbeta1-->3(Galbeta1-->6)GalNAc, whereas egg-secreted O-glycans carried the mucin-type core 1 (Galbeta1-->3GalNAc) and 2 (Galbeta1-->3(GlcNAcbeta1-->6)GalNAc) structures. Additionally we identified a novel O-glycan core in both secretions in which a Gal residue is linked to the protein. Terminal structures of N- and O-glycans contained high levels of fucose and include stage-specific structures. These glycan structures identified in S. mansoni secretions are potentially antigenic motifs and ligands for carbohydrate-binding proteins of the host immune system.     

Differential responsiveness to immunoablative therapy in refractory rheumatoid arthritis is associated with level and avidity of anti-cyclic citrullinated protein autoantibodies: a case study

In order to identify pathogenic correlates of refractory rheumatoid arthritis (RA), antibodies against anti-cyclic citrullinated protein (ACPAs) were investigated in RA patients in whom the dysregulated immune system had been ablated by high-dose chemotherapy (HDC) and autologous haematopoietic stem cell transplantation (HSCT). Six patients with refractory RA were extensively characterized in terms of levels of total immunoglobulins, RA-specific autoantibodies (ACPAs and rheumatoid factor) and antibodies against rubella, tetanus toxoid (TT) and phosphorylcholine before and after HDC plus HSCT. Additionally, the avidity of ACPAs was measured before and after treatment and compared with the avidity of TT antibodies following repeated immunizations. Synovial biopsies were obtained by arthroscopy before HDC plus HSCT, and analyzed by immunohistochemistry. In the three patients with clinically long-lasting responses to HDC plus HSCT (median 423 days), significant reductions in ACPA-IgG levels after therapy were observed (median level dropped from 215 to 34 arbitrary units/ml; P = 0.05). In contrast, stable ACPA-IgG levels were observed in three patients who relapsed shortly after HDC plus HSCT (median of 67 days). Clinical responders had ACPA-IgG of lower avidity (r = 0.75; P = 0.08) and higher degree of inflammation histologically (r = 0.73; P = 0.09). Relapse (after 38 to 530 days) in all patients was preceded by rising levels of low avidity ACPA-IgG (after 30 to 388 days), in contrast to the stable titres of high avidity TT antibodies. In conclusion, humoral autoimmune responses were differentially modulated by immunoablative therapy in patients with synovial inflammation and low avidity ACPA-IgG autoantibodies as compared with patients with high levels of high avidity ACPA-IgG. The distinct clinical disease course after immunoablative therapy based on levels and avidity of ACPA-IgG indicates that refractory RA is not a single disease entity.     

Flufenamic acid is a tool for investigating TRPC6-mediated calcium signalling in human conditionally immortalised podocytes and HEK293 cells

Mutations in the cation channel TRPC6 result in a renal-specific phenotype of familial nephrotic syndrome, affecting intracellular calcium ([Ca²⁺]_i) signalling in the glomerular podocyte. Tools to study native TRPC6 activity are scarce, although there has been recent success with flufenamic acid (FFA). We confirm the specificity of FFA for TRPC6 both in an artificial expression system and in a human conditionally immortalised podocyte cell line (ciPod).Cells were loaded with fura-2AM and changes in intracellular calcium ([Ca²⁺]_i) were calculated. 200 μM FFA induced an increase in [Ca²⁺]_i in HEK293 cells with native TRPC6 expression, which was enhanced by overexpression of TRPC6 and completely blocked in the absence of extracellular calcium. Expressed TRPC7 did not significantly affect the response to FFA whereas expressed TRPC3 reduced it. FFA also induced an increase ciPod in [Ca²⁺]_i, which was inhibited using SKF96365 and 2-APB, but not indomethacin. In ciPod, adenovirus (Ad-v) wild type (WT) TRPC6 increased [Ca²⁺]_i activity to FFA compared to native TRPC6, whereas activity was significantly reduced with Ad-v dominant negative (DN) TRPC6. The niflumic acid (NFA) induced increase in [Ca²⁺]_i in ciPod was not affected by Ad-v TRPC6 DN, and in HEK293 cells was not affected by WT TRPC6.In conclusion, FFA activates TRPC6 [Ca²⁺]_i signalling in both ciPod and HEK293 cells independently of TRPC3 and TRPC7, and independently of properties of the fenamate family.     

Transitional cell carcinoma of the ovary: A rare case and review of literature

Goblet cell carcinoid of the large intestine is a rare neoplasm, usually located in ascending colon and rectum. A 60-year-old male patient underwent surgery after the diagnosis of acute abdomen. Exploratory laparotomy revealed perforation with a diameter of 1 cm at the site of the previously performed gastroenterostomy and dilatation of the right colic flexure, secondary to a solid obstructive mass located in the mid-portion of transverse colon. Histopathological investigation of the biopsies, taken from the gastroenterostomy site and the tumor, revealed mixed carcinoid-adenocarcinoma with carcinoid component, predominantly composed of goblet cells. Three cycles of FOLFOX-4 protocol was administered. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and subsequently died in the fourth postoperative month. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm.