Toward Near-Infrared Emission in Pt(II)-Cyclometallated Compounds: From Excimers' Formation to Aggregation-Induced Emission

Two series of Pt(II)-cyclometallated compounds containing N^C^N tridentate and alkynyl-chromophore ligands have been synthesized and structurally characterized. The N^C^N ligands differ on the presence of R₁ = H or F in the central aromatic ring, while six different chromophores have been introduced to the alkynyl moiety. Single-crystal X-ray structures for some of the compounds reveal the presence of weak intermolecular contacts responsible for the formation of some dimers or aggregates. The photophysical characterization shows the presence of two emission bands in solution assigned to the ³π-π* transition from the N^C^N ligands mixed with ³MLCT/³ILCT transitions (higher energy band) in deaerated samples. The formation of excimers has also been identified as a broad band at longer wavelengths [near-infrared (NIR) emission] that becomes the main emission band for compounds containing phenanthrene as the chromophore. NIR emission behavior has also been explored using acetonitrile/water mixtures, and the presence of aggregates that emit at ca. 650 nm has also been detected.

Improving the emission quantum yield in dinuclear Eu(iii) and Tb(iii) complexes with 2-fluorobenzoate

Luminescence studies performed on Ln(iii) compounds with the formula [Ln2(μ2-2FBz)4(2FBz)2(H-2FBz)2(H2O)2] for Ln = Eu (1) and Tb (2) indicate improved luminescence emission.

Room-Temperature Phosphorescence and Efficient Singlet Oxygen Production by Cyclometalated Pt(II) Complexes with Aromatic Alkynyl Ligands

The synthesis of five novel cyclometalated platinum(II) compounds containing five different alkynyl-chromophores was achieved by the reaction of the previously synthesized Pt-Cl cyclometalated compound (1) with the corresponding RC≡CH by a Sonogashira reaction. It was observed that the spectral and photophysical characteristics of the cyclometalated platinum(II) complexes (Pt-Ar) are essentially associated with the platinum-cyclometalated unit. Room-temperature emission of the Pt-Ar complexes was attributed to phosphorescence in agreement with DFT calculations. Broad nanosecond (ns)-transient absorption spectra were observed with decays approximately identical to those obtained from the emission of the triplet state. From the femtosecond-transient absorption (fs-TA) data, two main excited-state decay components were identified: one in the order of a few picoseconds was assigned to fast intersystem crossing to populate the triplet excited-state and the second (hundreds of ns) was associated with the decay of the transient triplet state. In general, efficient singlet oxygen photosensitization quantum yields were observed from the triplet state of these complexes.

Luminescent PtII and PtIV Platinacycles with Anticancer Activity Against Multiplatinum-Resistant Metastatic CRC and CRPC Cell Models

Platinum-based chemotherapy persists to be the only effective therapeutic option against a wide variety of tumours. Nevertheless, the acquisition of platinum resistance is utterly common, ultimately cornering conventional platinum drugs to only palliative in many patients. Thus, encountering alternatives that are both effective and non-cross-resistant is urgent. In this work, we report the synthesis, reduction studies, and luminescent properties of a series of cyclometallated (C,N,N')Pt^IV compounds derived from amine-imine ligands, and their remarkable efficacy at the high nanomolar range and complete lack of cross-resistance, as an intrinsic property of the platinacycle, against multiplatinum-resistant colorectal cancer (CRC) and castration-resistant prostate cancer (CRPC) metastatic cell lines generated for this work. We have also determined that the compounds are effective and selective for a broader cancer panel, including breast and lung cancer. Additionally, selected compounds have been further evaluated, finding a shift in their antiproliferative mechanism towards more cytotoxic and less cytostatic than cisplatin against cancer cells, being also able to oxidize cysteine residues and inhibit topoisomerase II, thereby holding great promise as future improved alternatives to conventional platinum drugs.

Luminescence studies of new [C,N,N′] cyclometallated platinum(ii) and platinum(iv) compounds

New [C,N,N′]-cyclometallated platinum(ii) and platinum(iv) complexes are prepared and their emission properties are reported.

The influence of floral symmetry, dependence on pollinators and pollination generalization on flower size variation

BACKGROUND AND AIMS

The pollinator-mediated stabilizing selection hypothesis suggests that the specialized pollination system of zygomorphic flowers might cause stabilizing selection, reducing their flower size variation compared with actinomorphic flowers. However, the degree of ecological generalization and of dependence on pollinators varies greatly among species of both flower symmetry types and this may also affect flower size variation.

METHODS

Data on 43 species from two contrasting communities (one alpine and one lowland community) were used to test the relationships and interactions between flower size phenotypic variation, floral symmetry, ecological pollination generalization and species' dependence on pollinators.

KEY RESULTS

Contrary to what was expected, higher flower size variation was found in zygomorphic than in actinomorphic species in the lowland community, and no difference in flower size variation was found between symmetry types in the alpine community. The relationship between floral symmetry and flower size variation depended on ecological generalization and species' dependence on pollinators, although the influence of ecological generalization was only detected in the alpine community. Zygomorphic species that were highly dependent on pollinators and that were ecologically specialized were less variable in flower size than ecologically generalist and selfing zygomorphic species, supporting the pollinator-mediated stabilizing selection hypothesis. However, these relationships were not found in actinomorphic species, probably because they are not dependent on any particular pollinator for efficient pollination and therefore their flower size always shows moderate levels of variation.

CONCLUSIONS

The study suggests that the relationship between flower size variation and floral symmetry may be influenced by population-dependent factors, such as ecological generalization and species' dependence on pollinators.

ZEB1 represses E-cadherin and induces an EMT by recruiting the SWI/SNF chromatin-remodeling protein BRG1

Loss of E-cadherin is a key initial step in the transdifferentiation of epithelial cells to a mesenchymal phenotype, which occurs when tumor epithelial cells invade into surrounding tissues. Expression of the nuclear factor ZEB1 induces an epithelial-to-mesenchymal transition and confers a metastatic phenotype on carcinomas by repressing the E-cadherin gene at the transcriptional level. In this study, we show that ZEB1 interacts with the SWI/SNF chromatin-remodeling protein BRG1 to regulate E-cadherin independently of CtBP, its traditional co-repressor. Blocking the interaction between ZEB1 and BRG1 induces expression of E-cadherin and downregulation of the mesenchymal marker vimentin. ZEB1 and BRG1 colocalize in E-cadherin-negative cells from cancer lines and in the stroma of normal colon. Colocalization of ZEB1 and BRG1 in epithelial cells is only found in those de-differentiated cells characterized by nuclear beta-catenin staining at the invasive edge of the tumor. Our results identify ZEB1/BRG1 as a new transcriptional mechanism regulating E-cadherin expression and epithelial-to-mesenchymal transdifferentiation that may be involved during the initial stages of tumor invasion.

[A guide to the clinical diagnosis and urgent treatment of neonatal hyperammonaemia]

Symptomatic hyperammonaemia in newborn is a medical emergency that should be recognised in its early stages, specifically diagnosed and aggressively treated to improve the immediate and long-term prognosis of these children. The paediatrician and the neonatal doctor should have a diagnosis-therapy scheme for its urgent management.

Variation in sexual expression in the monoecious shrub Buxus balearica at different scales

Monoecy allows high plasticity in gender expression because the production of separate female and male flowers increases the ability to respond to specific environmental circumstances. We studied variation in sexual expression and its correlates in the monoecious shrub Buxus balearica, for two years, in six populations in the Balearic Islands and four in the Iberian Peninsula. Phenotypic gender varied among populations; while island populations showed slight variations around an average gender, mainland populations showed a broad range of variation in gender among individuals, always biased towards increasing maleness compared with the other populations. Within populations, gender was not related to plant size. Between-year changes were slight and mainly consisted of an increase in relative maleness in the mast year. Reproduction did not affect gender in the next year, as assessed by either observational or experimental methods. Most variation in gender expression occurred among individuals within populations (83.6 %), followed by variation among populations (13.6 %) and years (2.8 %). Our results suggest that male-biased gender at population and plant levels was related to stressful conditions and resource limitation, because: (1) maleness was higher in mainland populations, where summer drought was stronger; (2) maleness increased with elevation; (3) fruit set was positively correlated with femaleness; (4) the percentage of male inflorescences increased over the flowering period; and (5) male inflorescences were preferentially in lower parts of the branch nodes. Higher maleness in mast years, however, could be related to increased male success under synchronic flowering.

Down-Regulation of Matrix Metalloproteinase-9 (MMP-9) Expression in the Myocardium of Congestive Heart Failure Patients

Matrix metalloproteinases (MMPs) are proteolytic enzymes responsible for extracellular matrix protein degradation. They have an important role in tissue remodeling processes. Their activity is regulated at the transcriptional, translational, and posttranslational level and by tissue inhibitors (TIMPs). Our aim was to analyze whether expression changes in MMPs that degrade collagens and their inhibitors in the myocardium have an impact on ventricular remodeling and the fibrogenesis in congestive heart failure.

METHODS

We analyzed left ventricle biopsies from 18 patients with idiopathic dilated cardiomyopathy (iCDM) and severe congestive heart failure (HF) and 13 biopsies from organ donors. mRNA expression was quantified by real-time PCR, and fibrosis levels measured with picrosirius red staining.

RESULTS

The patients mean age was 53 +/- 3 years. Expression levels of MMP-1, MMP-2, MMP-3, and TIMP1 did not show differences in pathological hearts compared to control hearts. Expression levels of MMP-1 and MMP-3 were low. MMP-9 expression levels were down-regulated in the cardiomyopathic hearts (49.77 +/- 7.6 ng equivalents of cDNA [ng-eq]) compared to controls (91.24 +/- 10.8 ng-eq, P < .005). MMP-2 expression levels correlated with the fibrosis levels (P < .05, R2 = 0.33, n = 18).

CONCLUSION

MMP-9 mRNA expression down-regulation suggested that the protein levels were regulated at the posttranscriptional level. The correlation between MMP-2 expression levels and the collagen fraction in the pathological hearts indicated a putative role of MMP-2 in the fibrosis that takes place in congestive heart failure.

Correlation Between Mast Cell Density and Myocardial Fibrosis in Congestive Heart Failure Patients

Besides the well-established role of mast cells in allergic reactions as an important source of vasoactive and proinflammatory products, they have been related to tissue fibrosis and remodelling processes. In a heart failure (HF) animal model, mast cells were shown to synthesize transforming growth factor beta1 and basic fibroblast growth factor in myocardial tissue and were localized to an area with fibrosis. Our objective was to quantify mast cell density in left ventricles from patients with congestive heart failure who were candidates for transplantation and to analyze whether they showed a correlation with the fibrosis level of the same area.

METHODS

We obtained myocardial biopsies from 20 patients with end-stage HF secondary to idiopathic dilated cardiomyopathy (iDCM) undergoing heart transplantation and 15 controls (donors without cardiopathy). Mast cells were detected by immunohistochemistry with a human mast cell chymase antibody and fibrosis levels measured with picrosirius red staining of collagen fibrils with later quantification by morphometry.

RESULTS

The patients mean age was 51 +/- 3 years. Fibrosis levels in the myocardial sections from patients with congestive HF was three-fold higher than those in control myocardium (12.41 +/- 1.7% vs 3.98 +/- 0.63%, P < .001). Mast cell density correlated with the collagen fraction and could be fitted to a linear regression curve: collagen fraction = 0.78 + 0.05 mast cell density (n = 33, P < .005, R2 = 0.28).

CONCLUSION

The elevated collagen fraction present in failing hearts may be the cause of increased stiffness and loss of elasticity that is detected in patients with end-stage HF. Due to the mast cells capacity to synthesize vasoactive and fibrogenic products and the correlation between their density and fibrosis levels, they probably play a role in the ventricular remodelling in HF.

Ouabain Binding to Na+,K+-ATPase Relaxes Cell Attachment and Sends a SpecificSignal (NACos) to the Nucleus

Abstract. In previous work we described a "P-->A mechanism" that transduces occupancy of the pump ( P) by ouabain into changes in phosphorylation, stimulation of mitogen-activated protein kinase (MAPK), and endocytosis of cell-cell- and cell-substrate-attaching molecules ( A), thereby causing a release of the cell from the monolayer. In the present work we try to understand the mechanism of this effect; whether, in order to trigger the P-->A mechanism, ouabain should block the pumping activity of Na(+),K(+)-ATPase as pump, or whether it would suffice that the drug occupies this enzyme as a receptor. We assay a series of drugs known to act on the pump, such as ouabain, digoxin, digitoxin, palytoxin, oligomycin, strophanthidin, neothyoside-A, proscillaridin-A, etc. We gauge their ability to block the pump by measuring the K(+) content in the cells, and their ability to detach the cells from the monolayer by determining the amount of protein remaining in the culturing well. None of the drugs tested was able to cause detachment without stopping the pump. Ouabain also enhances phosphorylation, yet pump inhibition and signal transduction do not seem to be intimately associated in a causal chain, but to occur simultaneously. To investigate the response of the site of cell attachment, we analyze the position of beta-catenin by fluorescence confocal microscopy, and find that this adherent junction-associated molecule is sent to the nucleus, where it is known to act as a transcriptional cofactor.

Dietary fat intake and body mass index in Spanish children

Our objectives were to describe the pattern of dietary fat intake and to present data on trends of growth in Spanish children in past decades. In 1984 a nationwide nutritional survey was conducted in Spain. The average nationwide fat intake was 42% of energy. Across different regions, saturated fat intakes ranged from 13% to 15% of energy and monounsaturated fat intakes ranged from 18% to 19% of energy. More recently, some surveys were conducted at a regional or local level. In children aged 6-10 y, total fat intake ranged from 38% to 48% of energy, of which saturated fat intake ranged from 16% to 18% and monounsaturated fat ranged from 19% to 20%. In children aged 11-14 y, total fat intake ranged from 41% to 51% of energy, of which saturated fat intake ranged from 12% to 18% and monounsaturated fat intake accounted for 20%. In our region of Aragón, we observed a significant trend in children's growth, especially when we accounted for body mass index. The results reflect an increasing total fat consumption in Spain, especially of saturated and monounsaturated fat. The following question remains unanswered: what percentage of fat intake should be recommended when monounsaturated fat is the principal source of fat? Trends on body mass index values in children of our region during the past decades could be related to the amount of fat intake in our population. To confirm these findings we must measure dietary fat intake and nutritional status in the same population of children and adolescents.

Lymphocyte T subset counts in children with hypercholesterolemia receiving dietary therapy

BACKGROUND

In children with hypercholesterolemia, dietary therapy is indicated; however, we do not know if a low-fat diet can modify some organic functions, i.e. immune function.

METHODS

42 children with hypercholesterolemia received a low-fat, low-cholesterol diet during 6 months. At baseline and after the treatment period, we determined a lipoprotein profile and some immune characteristics: immunoglobulins G, A and M; complement components (C3, C4 and factor B), and blood lymphocyte subsets (CD3, CD4 and CD8).

RESULTS

Total cholesterol serum concentrations showed a significant reduction after 6 months of dietary therapy (p = 0.008). After 6 months on a low-fat diet, lymphocyte T subset counts (CD3, CD4 and CD8) showed significant decreases (p < 0.01 to p < 0.003), but lymphocyte counts were always within normal ranges. There was also a significant correlation between changes in some lymphocyte T subset counts (CD3 and CD8) and changes in triglyceride serum concentrations (p < 0.05).

CONCLUSIONS

A low-fat, low-cholesterol diet diminished CD3, CD4 and CD8 lymphocyte subset counts that are elevated in children with hypercholesterolemia. Dietary therapy, with emphasis on the intake of n-3 fatty acids, could be useful in the modulation of the immune response at the atheromatous plaque level.

New Natural Hosts of Tomato spotted wilt virus

Tomato spotted wilt virus (TSWV) has caused epidemics in recent years in many crops throughout the Mediterranean Region. Tomato, pepper, and lettuce are the crops most affected in Spain. To determine the reservoir hosts for the virus in the area, 210 samples from 95 species of plants were collected and tested for TSWV by double-antibody sandwich enzyme-linked immunosorbent assay with commercial antisera (Loewe Biochemica, Germany: BR-01, serogroup I or TSWV-L). Twenty-one species tested positive, and among them were thirteen newly identified hosts for TSWV (1). Weed species were among the 13 new hosts and included Diplotaxis erucoides (L.) DC., Beta maritima L., Phragmites communis Trin., Malva sylvestris L., Sonchus arvensis L., Sorghum halepense L., Panicum repens L., Atriplex patula L., Coronopus squamatus (Forssk.) Ascherson, Cuscuta sp., Xanthium spinosum L., Suaeda vera J.F., and Ecballium elaterium (L.) A. Rich. Most of these plants were asymptomatic hosts, but the Sonchus sp. showed typical symptoms of TSWV, such as yellows, bronzing, ring spots, necrosis, curling of young leaves, and growth reduction. D. erucoides, B. maritima, M. sylvestris, X. spinosum, and E. elaterium showed chlorosis and growth reduction. Reference: (1) C. Jorda et al. 1998. Anexo no. 3. Pages 381-386 in: The Health of Tomato Crops. Phytoma-España S. L., Valencia, Spain.

[Multicenter study of the variability and adequacy of antimicrobial therapy for community-acquired pneumonia in adults]

We performed a study to evaluate the variability and adequacy of prescribing antibiotics in community-acquired pneumonia (CAP) in 10 Spanish hospitals. We studied 452 patients with CAP. Initial empirical administration of antibiotics was prescribed in 90.7&#37; of the cases, 82.5&#37; as monotherapy. Macrolides and third and second generation cephalosporins were the most widely used groups of antibiotics. Penicillin and amoxicillin were only prescribed in 1. 7&#37; of the patients. A significant variability between hospitals was observed. Reference patterns for the use of antibiotics in CAP were devised by a panel of experts. According to the recommendations of this panel, 29&#37; of the total prescriptions were not adequate, with this percentage reaching 65&#37; in outpatients older than 65 years or with comorbidity. This was mainly due to the fact that monotherapy with erythromycin, which was considered inadequate, was the most widely prescribed treatment.

Relationship between Na(+),K(+)-ATPase and cell attachment

A prolonged ouabain blockade of the Na(+),K(+)-ATPase detaches cells from each other and from the substrate. This suggests the existence of a link between pump (P) and attachment (A). In the present work, we report that MDCK-W cells treated with ouabain increase tyrosine phosphorylation and content of active MAP kinase, redistribute molecules involved in cell attachment (occludin, ZO-1, desmoplakin, cytokeratin, alpha-actinin, vinculin and actin), and detach. Genistein and UO126, inhibitors of protein tyrosine kinase and of MAP kinase kinase, respectively, block this detachment. The content of P190(Rho-GAP), a GTPase activating protein of the Rho small G-protein subfamily, is increased by ouabain, suggesting that both the Rho/Rac and MAPK pathways are involved. Another clone of MDCK cells whose Na(+),K(+)-ATPase has a negligible affinity for the drug, show none of the effects described for MDCK-W and remain attached. Ma104 cells, a line that has a high affinity for ouabain and stops pumping, fail to modify phosphorylation, as well as the pattern of distribution of attaching molecules, and remain in the monolayer. Taken together, these results suggest that there is a mechanism (P--&gt;A) that transduces a blockade of the pump in a detachment of the cell from neighbors and substrate, in which Ma104 cells are faulty.

[Practice variation and appropriateness study of antimicrobial therapy for acute pharyngotonsillitis in adults]

OBJECTIVE

Infectious pharyngotonsillitis is usually managed with antibiotics by general practitioners and pediatricians both in primary care and the emergency services. In the present work we try to assess the antibiotic variability and appropriateness in the management of acute pharyngotonsillitis among several emergency services in our country related to scientific evidence based in an expert panel criteria.

METHOD

A transversal trial was carried on in ten emergency services of our country. We included patients older than fourteen years an analyzed the following variables: type of respiratory infection, antibiotic prescription, comorbidity, physician's status and hospital admission. The antibiotics were classified in three levels according to the expert panel criteria: first election, alternative use and inappropriate use. We compared the antibiotic treatments to these three levels.

RESULTS

2,869 patients were diagnosed of acute respiratory infection, 356 (12.4%) with pharyngotonsillitis. Commonly the patients were prescribed antibiotics (315; 81%) and the most used were amoxicillin-clavulanate (33%), amoxicillin (16%), penicillin (7%), cefuroxime (6%), erythromicin (4%) and cefixime (3%). Among the 315 prescriptions, 98 (32%) were first election, 147 (50%) alternative use and 50 (17%) inappropriate use.

CONCLUSIONS

Most of the patients suffering of pharyngotonsillitis were empirically prescribed antibiotics probably many of these cases were non-bacterial pharyngotonsillitis. Alternative and inappropriate use of antibiotics was high.

[Effectiveness of topical anesthesia enhanced by sedation and analgesia for cataract surgery]

OBJECTIVES

To compare the efficacy of topical anesthesia and retrobulbar anesthesia for cataract surgery by lens emulsification.

PATIENTS AND METHODS

Two hundred sixty patients were randomized to two groups in this open clinical trial. Patients with cataracts that could not be treated by lens emulsification were excluded. Group I patients (n = 129) received 0.5% tetracaine drops and intravenous fentanyl and propofol, along with continuous sedation. Group II patients (n = 131) received 2% lidocaine in the retrobulbar space and hypnotic doses of intravenous propofol before retrobulbar injection. The anesthesiologist evaluated anesthesia negatively if SpO2 was 90% and either heart rate or blood pressure varied more than 20%. The ophthalmologist evaluated anesthesia negatively if the eye did not remain fixed in the center, if blepharospasm appeared or if the anterior chamber of the eye collapsed. The patient reported the intensity of any discomfort experienced on a six-point scale. Anesthesia was determined to be effective when favorable evaluations were given by both the anesthesiologist and the ophthalmologist and when no significant discomfort (first three points on the scale) was reported by the patient. The two treatment groups were compared using a single and multiple factor analysis.

RESULTS

Group II experienced significantly fewer instances of ineffective anesthesia than did group I (8 versus 22) and fewer negative evaluations by the ophthalmologists (7 versus 18). More patients in group I reported discomfort than in group II (46 versus 9), although most complaints were of slight discomfort. Multiple factor analysis showed that a patient in group I had 4.64 more chances of experiencing ineffective anesthesia.

CONCLUSIONS

Topical anesthesia is less effective than retrobulbar anesthesia for cataract surgery by lens emulsification.

Tight junctions and the experimental modifications of lipid content

Tight junctions (TJs) are cell-to-cell contacts made of strands, which appear as ridges on P faces and complementary furrows on E faces on freeze fracture replicas. Evidences and opinions on whether these strands are composed of either membrane-bound proteins or lipid micelles are somewhat varied. In the present work we alter the lipid composition of Madin-Darby canine kidney monolayers using a novel approach, while studying (i) their transepithelial electrical resistance, a parameter that depends on the degree of sealing of the TJs; (ii) the apical-to-basolateral flux of 4 kD fluorescent dextran (JDEX), that reflects the permeability of the intercellular spaces; (iii) the ability of TJs to restrict apical-to-basolateral diffusion of membrane lipids; and (iv) the pattern of distribution of endogenous and transfected occludin, the sole membrane protein presently known to form part of the TJs. We show that changing the total composition of phospholipids, sphingolipids, cholesterol and the content of fatty acids, does not alter TER nor the structure of the strands. Interestingly, enrichment with linoleic acid increases the JDEX by 631%. The fact that this increase is not reflected in a decrease of TER, suggests that junctional strands do not act as simple resistive elements but may contain mobile translocating mechanisms.

Relationship between immunoinflammatory proteins containing sialic acid and low-density lipoprotein serum concentrations

The aim of this study was to investigate the relationship between sialoglycoproteins and the lipoprotein profile in a group of children with different levels of low-density lipoprotein cholesterol. We have studied 177 children of 132 families who were sent to our Pediatric Lipid Research Clinic because of serum cholesterol concentrations higher than 5.17 mmol/l. At the time of diagnosis, we analyzed the serum lipoprotein profile and the sialoglycoproteins: alpha 1-antitrypsin, acid alpha 1-glycoprotein, haptoglobin, alpha 2-macroglobulin, transferrin, IgA, IgG, IgM, complement C3 component and ceruloplasmin. At 7.0 to 10.9 years, alpha 1-glycoprotein serum concentrations were higher in the high risk group than in the moderate risk group (P < 0.05). At 2.0 to 6.9 years, IgA and IgM serum concentrations were higher in the moderate risk group than in the low risk group (P < 0.05 and P < 0.01, respectively), and IgG and IgM serum concentrations were also higher in the high risk group than in the low risk group (P < 0.05). Our results seems to reflect a general reaction to injury or inflammation which could be associated with the atherosclerotic process.

Lymphocyte T subset counts in children with elevated low-density lipoprotein cholesterol levels

The aim of this study was to determine blood lymphocyte T subset counts in children with elevated levels of low-density lipoprotein cholesterol. We studied 107 children, ages 2.0 to 15.9 years, from 79 families who were referred to our Lipid Research Clinic because total cholesterol serum levels higher than 200 mg/dl had been detected in at least one child. At the time of diagnosis we analyzed serum lipoprotein profile and blood lymphocyte T subsets (CD3, CD4 and CD8). Children were classified according to LDL-C levels into three groups: (1) normal, if levels were between the 5th and 75th percentiles (50 and 125 mg/dl, respectively); (2) at moderate risk, if levels were between the 75th and 95th percentiles (125 and 150 mg/dl, respectively); and (3) at high risk, if levels were above the 95th percentile (150 mg/dl). In children aged 2.0 to 6.9 years, all lymphocyte T subset counts were higher in the high risk group than in the normal group (P < 0.05 and P < 0.01). In children aged 11.0 to 15.9 years, the CD4 subset count was also significantly higher in the high risk group in the other two groups (P < 0.05 and P < 0.01). These results are in agreement with pathologic findings in the atheromatous plaque.

A novel type of cell-cell cooperation between epithelial cells

Ma104 cells (renal, epithelial) have a peculiar way of resisting ouabain: their Na+,K(+)-pumps bind the drug with high affinity, cellular K+ is lost and cell division arrested, but cells do not detach as most cell types do. Then, if up to 4 days later the drug is removed, Ma104 cells recover K+ and resume proliferation (Contreras et al., 1994). In the present work, we investigate whether Ma104 cells are able to protect ouabain-sensitive MDCK cells in co-culture. The main finding is that they do, but in this case protection is not elicited by the usual mechanism of maintaining the K+ content of neighboring cells through cell-cell communications. Ma104 cells treated with ouabain simply remain attached to the substrate and to their MDCK neighbors, and both cells lose K+. This attachment includes tight junctions, because the transepithelial electrical resistance of the monolayers is not abolished by ouabain. Although the beta-subunit of the Na+,K(+)-ATPase is known to possess molecular characteristics of cell-cell attachment molecules, attachment between Ma104-MDCK cells does not seem to be mediated by this enzyme, as immunofluorescence analysis reveals that Na+,K(+)-ATPase is only inserted in the plasma membrane facing a neighboring cell of the same type.

Ouabain resistance of the epithelial cell line (Ma104) is not due to lack of affinity of its pumps for the drug

Na+, K(+)-pumps of most eukaryotic animal cells bind ouabain with high affinity, stop pumping, and consequently loose K+, detach from each other and from the substrate, and die. Lack of affinity for the drug results in ouabain resistance. In this work, we report that Ma104 cells (epithelial from Rhesus monkey kidney) have a novel form of ouabain-resistance: they bind the drug with high affinity (Km about 4 x 10(-8) M), they loose their K+ and stop proliferating but, in spite of these, up to 100% of the cells remain attached in 1.0 microM ouabain, and 53% in 1.0 mM. When 4 days later ouabain is removed from the culture medium, cells regain K+ and resume proliferation. Strophanthidin, a drug that attaches less firmly than ouabain, produces a similar phenomenon, but allows a considerably faster recovery. This reversal may be associated to the fact that, while in ouabain-sensitive MDCK cells Na+, K(+)-ATPases blocked by the drug are retrieved from the plasma membrane, those in Ma104 cells remain at the cell-cell border, as if they were cell-cell attaching molecules. Cycloheximide (10 micrograms/ml) and chloroquine (10 microM) impair this recovery, suggesting that it also depends on the synthesis and insertion of a crucial protein component, that may be different from the pump itself. Therefore ouabain resistance of Ma104 cells is not due to a lack of affinity for the drug, but to a failure of its Na+, K(+)-ATPases to detach from the plasma membrane in spite of being blocked by ouabain.

Effect of low doses of deflazacort vs prednisone on bone mineral content in premenopausal rheumatoid arthritis

Longterm administration of steroid drugs, particularly prednisone, is known to induce osteoporosis, as well as bone growth inhibition and delayed fracture union. Recently deflazacort, an oxazoline prednisone derivative, has been developed to reduce such deleterious effects. We carried out a comparative study in premenopausal patients with rheumatoid arthritis (RA). Sixteen cases whose mean age was 36.5 years and mean disease duration 29 months, all fulfilling ARA criteria, were evaluated in a randomized, double blind trial. Visually identical deflazacort or prednisone capsules were given and patients were instructed to maintain an adequate calcium intake. Laboratory tests focussed on bone mineral density in lumbar spine, femoral neck and Ward's triangle and whole body mineral content. Differences between baseline and 12-month values were processed statistically. Persistent synovitis control proved similar for both drugs and features suggestive of Cushing's syndrome were only found in the prednisone group. The difference in whole body bone mineral content between the deflazacort and prednisone groups just failed to reach statistical significance. In the deflazacort group, the difference between the nonsignificant bone mineral density increase at the femoral neck and the significant decrease in the prednisone group proved statistically significant. Ward's triangle was the most sensitive area to bone mineral density changes in patients receiving prednisone, with a highly significant intergroup difference (p < 0.01). We believe this is the first study on corticosteroid induced osteoporosis, as evaluated by whole body mineral content measurements in premenopausal patients with short term RA, showing that deflazacort is a promising alternative in cases severe enough to require steroid therapy.

Usefulness of serum apolipoprotein B levels for screening children with primary dyslipoproteinemias

OBJECTIVE

To assess the use of serum apolipoprotein B levels for screening children with primary dyslipoproteinemia (those with elevated levels of low-density lipoprotein cholesterol [LDL-C]) and to know the types of dyslipoproteinemias we can identify.

DESIGN

Criterion standard.

SETTING

Referral center.

PARTICIPANTS

We have studied 267 children. Of these, 31 had parents with dyslipoproteinemia, 38 had parents with ischemic heart disease, and 43 had hypercholesterolemia detected by routine analyses. One hundred fifty-five were considered healthy children and comprised the control group.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Sensitivity was 87% for total serum cholesterol levels and 73% for serum apolipoprotein B levels. Of the children studied, 31 had elevated levels of serum LDL-C. The types of dyslipoproteinemia in children with both elevated levels of serum LDL-C and apolipoprotein B consisted of heterozygous familial hypercholesterolemia, found in 12 (50%) of 24 patients; familial combined hyperlipidemia, found in 11 (46%) of 24 patients; and polygenic hypercholesterolemia, found in one (4%) of 24 patients.

CONCLUSIONS

Serum apolipoprotein B level appears to be a good tool for screening children with elevated levels of LDL-C and is equivalent to using total serum cholesterol levels. In children with elevated serum LDL-C and apolipoprotein B levels, we can identify not only patients with heterozygous familial hypercholesterolemia but also those with familial combined hyperlipidemia or polygenic hypercholesterolemia.

Osmolarity-sensitive release of free amino acids from cultured kidney cells (MDCK)

The amino acid pool of MDCK cells was essentially constituted by alanine, glycine, glutamic acid, serine, taurine, lysine, beta-alanine and glutamine. Upon reductions in osmolarity, free amino acids were rapidly mobilized. In 50% hyposmotic solutions, the intracellular content of free amino acids decreased from 69 to 25 mM. Glutamic acid, taurine and beta-alanine were the most sensitive to hyposmolarity, followed by glycine, alanine and serine, whereas isoleucine, phenylalanine and valine were only weakly reactive. The properties of this osmolarity-sensitive release of amino acids were examined using 3H-taurine. Decreasing osmolarity to 85, 75 or 50% increased taurine efflux from 0.6% per min to 1.6, 3.5 and 5.06 per min, respectively. The time course of 3H-taurine release closely follows that of the regulatory volume decrease in MDCK cells. Taurine release was unaffected by removal of Na+, Cl- or Ca2+, or by treating cells with colchicine or cytochalasin. It was temperature dependent and decreased at low pH. Taurine release was unaffected by bumetanide (an inhibitor of the Na+/K+/2Cl- carrier); it was inhibited 16 and 67 by TEA and quinidine (inhibitors of K+ conductances), unaffected by gadolinium or diphenylamine-2-carboxylate (inhibitors of Cl- channels) and inhibited 50% by DIDS. The inhibitory effects of DIDS and quinidine were additive. Quinidine but not DIDS inhibited taurine uptake by MDCK cells.

Establishment of tight junctions between cells from different animal species and different sealing capacities

Epithelial cells establish tight junctions (TJs) that offer an ample range of transepithelial electrical resistances (TER), in adjustment to physiological requirements. In the present work, we demonstrate that cells from different animal origins, co-cultured in monolayers, can make sealed TJs, suggesting that this structure has a basic universal structure. TJs cannot be established, however, if one of the partners does not normally express TJs, indicating that each neighbor has to contribute its moiety. Furthermore, we observe that clones of the same cell line, with widely different values of TER, do not differ in the number and length of their junctional strands, suggesting that the difference is due to their ability to express ionic channels traversing their strands. The value of TER achieved in mixed monolayers of cells of the same or different lines is the one that may be expected by taking into account the proportion of each type in the mixture and adding in parallel the electrical resistance that they exhibit in pure monolayers. Therefore, epithelial TJs appear to behave as parallel resistances.

Signal peptide homology between the sweet protein thaumatin II and unrelated cereal alpha-amylase/trypsin inhibitors

A cDNA clone (pUP-23) corresponding to a member of a protein family that includes inhibitors of trypsin and of heterologous alpha-amylases has been selected from a library derived from developing barley endosperm and its sequence has been determined. A stretch of 95 nucleotides that included the signal peptide and the first 8 residues of the mature protein was found to be homologous to an exactly equivalent region of the nucleotide sequence encoding the sweet protein thaumatin II. Evolutionary implications of this finding are discussed.

Autopsy as quality assurance in the intensive care unit

A prospective study of 100 autopsies was carried out. The clinical and pathologic diagnoses were made independently by intensivists and pathologists; at the end of the study, the differences were determined. There were seven Class I errors (which if detected before death, would probably have led to a change in management that might have resulted in cure or prolonged survival), six of these relating to the basic disease and one to the cause of death. Class II errors occurred in 15 patients, ten relating to the basic disease and five to the cause of death. In 61% of the patients, the major and minor diagnoses coincided. In 77% of the patients, the major diagnoses coincided. No relationship was found between the incidence of Class I and Class II errors and the length of the patients' stay in the ICU.

A dimeric inhibitor or insect alpha-amylase from barley. Cloning of the cDNA and identification of the protein

A cDNA clone, designated pUP-44, whose longest open reading frame codes for a protein that is homologous to the wheat alpha-amylase inhibitors, has been isolated from a library obtained from developing barley endosperm. The deduced sequence for the mature protein, which is 122 residues long, is preceded by a sequence of 30 residues which has the typical features of a signal peptide. A closely corresponding protein, designated BDAI-1, has been isolated from mature endosperm. BDAI-1 behaves as a dimer and inhibits the alpha-amylase from the insect Tenebrio molitor at concentrations that have no effect on salivary or pancreatic alpha-amylases.

Rescue of a wild-type MDCK cell by a ouabain-resistant mutant

When wild-type MDCK cells (W-MDCK) were cocultured in mixed monolayers with a ouabain-resistant mutant (R-MDCK), the wild-type cells were protected from the effect of ouabain up to concentrations as high as 100 microM. Rescue depended on the dose of ouabain and on the proportion of each cell type in the coculture. The survival of R-MDCK cells at 1 microM ouabain was not endangered by varying from 1:9 to 9:1 the proportion of W-MDCK cells to be rescued. Ouabain binding revealed two kinds of binding sites in R-MDCK cells, one with high and the other with low affinity. Only the high affinity site was present in W-MDCK cells. Electron probe analysis of individual cells revealed that rescued cells kept a high K and a low Na intracellular contents, similar to control cells. Histograms of intracellular K/Na in cocultured cells treated with ouabain were unimodal. Using microinjection of Lucifer yellow or electrophysiological techniques we estimated that at most 13% of the R-MDCK and W-MDCK cells may be connected at a given time through cell-to-cell junctions. Therefore permanent cell-to-cell communication did not seem to play a central role in the rescue. W-MDCK cells cocultured with R-MDCK cells and subsequently separated, were not rescued. Thus rescue did not seem to depend on the transfer from R-MDCK to W-MDCK cells of either ouabain-resistant Na-K pumps or of information to synthesize them. It is speculated that intercellular communications were sporadic events, so that all cells may become intermittently connected and rescued.