Electrohydrodynamic flow and colloidal patterning near inhomogeneities on electrodes.

Current density inhomogeneities on electrodes (of physical, chemical, or optical origin) induce long-range electrohydrodynamic fluid motion directed toward the regions of higher current density. Here, we analyze the flow and its implications for the orderly arrangement of colloidal particles as effected by this flow on patterned electrodes. A scaling analysis indicates that the flow velocity is proportional to the product of the applied voltage and the difference in current density between adjacent regions on the electrode. Exact analytical solutions for the streamlines are derived for the case of a spatially periodic perturbation in current density along the electrode. Particularly simple asymptotic expressions are obtained in the limits of thin double layers and either large or small perturbation wavelengths. Calculations of the streamlines are in good agreement with particle velocimetry experiments near a mechanically generated inhomogeneity (a "scratch") that generates a current density larger than that of the unmodified electrode. We demonstrate that proper placement of scratches on an electrode yields desired patterns of colloidal particles.

Early education of patients with chronic renal insufficiency: the Healthy Start program. Case study of the anemic patient.

The Healthy Start Clinic is a multidisciplinary program that provides education and appropriate clinical interventions for patients with chronic renal insufficiency. The overall goals of the program are to delay the progression of kidney disease and improve the quality of care at the initiation of renal replacement therapy. This report shows that, compared to those who do not participate in the program, Healthy Start patients have significantly higher albumin levels and are more likely to have fistulas in place at the initiation of dialysis. The Healthy Start model suggests a new and expanded role for nurses in helping to coordinate care for this growing patient population.

[The behavior of angiotensin-converting enzyme in patients with uveitis]. / Zachowanie sie enzymu konwertujacego angiotensyne w schorzeniach zapalnych blony naczyniowej.

UNLABELLED: Serum angiotensin-converting enzyme (ACE) is considered as a marker in many disorders, especially in sarcoidosis. The aim of this study was to assess ACE activity using Haiakari spectrophotometry in patients with non-sarcoidosis uveitis before and after treatment. MATERIAL AND METHODS: 36 patients, including 21 adults and 15 children, were investigated. ACE concentration was increased mostly in patients with recurrent toxoplasmic and toxocaral iridocyclitis and choroiditis. RESULTS: It was demonstrated that concentration of ACE was increased especially in toxocariasis uveitis. After treatment the concentration of ACE was significantly decreased in all patients.

[Evaluation of treatment and preventive care for recurrent urolithiasis in children]. / Ocena skutecznosci leczenia i profilaktyki kamicy nawrotowej ukladu moczowego u dzieci.

Among 425 children with urolithiasis treated in the Paediatric Clinical Department of the National Research Institute of Mother and Child in Warsaw between 1976-1997, 50 of them i.e. 11.7% (26 boys and 24 girls) had recurrent urolithiasis. Patients' age was from 10 months to 16 years and 5 months. The number of recurrences of uroliothiasis before treatment in the Institute was from 1 to 8. Most of the children had numerous surgical operations, some of them excreted stones spontaneously. The etiology was determined in all cases. A metabolic cause of urolithiasis was found in 34 cases, i.e. 68% of the analysed group. They were as follows: idiopathic hypercalcuria--24 cases, uric acid urolithiasis--5 cases, cystynuria--4 cases, and incomplete distal renal tubular acidosis--1 case. Other reasons for urolithiasis were: infection--7 cases, idiopathic urolithiasis--8 cases, ren spongiosum--1 case. Prevention of recurrences depending on the etiology was successful. In 45 cases no recurrences were found. Recurrent urolithiasis was observed in 4 cases of cystynuria and in one case of incomplete tubular acidosis. The observation period was from 3-19 years.

[Mutations causing hereditary hyperphenylalaninemia]. / Mutacje powodujace dziedziczna hiperfenyloalaninemie.

Mutations in the genes encoding different parts of phenylalanine hydroxylation system cause persistent hyperphenylalaninaemia. The most frequent form of hyperphenylalaninaemia is caused by mutations in the PAH gene. The most common variant result from defect of tetrahydrobiopterin synthase. Mutations in the PAH and PTS genes in the Polish population are presented. Genotype--phenotype correlations are discussed.

Evidence that tumor necrosis factor triggers apoptosis in human endothelial cells by interleukin-1-converting enzyme-like protease-dependent and -independent pathways.

Cultured human endothelial cells (EC) resist tumor necrosis factor (TNF)-mediated apoptosis. However, the combination of TNF and the protein synthesis inhibitor cycloheximide (CHX) induces apoptosis in up to 50% of EC within 24 hours. TNF + CHX killing is effectively blocked by transfected CrmA protein or treatment with Z-VAD.fmk peptide-both inhibitors of interleukin-1-converting enzyme-like proteases-but not by transfected antiapoptotic proteins Bcl-2, Bcl-XL, or A1. C6-ceramide (cer) can also sensitize EC to TNF-induced apoptosis. TNF + cer killing, which can affect more than 50% of EC, is not effectively inhibited by CrmA or Z-VAD frank, but can be readily blocked by Bcl-2, Bcl-XL, or A1. Both TNF + CHX and TNF+ cer killing are induced by a TNF mutein that only interacts with the type 1 TNF receptor, and both responses can be inhibited by the antiapoptotic protein A20. These data suggest that TNF activates two biochemically separable pathways of EC injury.

[Bilateral isolated posterior scleritis]. / Obustronne, izolowane zapalenie tylnej czesci twardówki.

A case of 44-year-old man is presented with no simultaneous bilateral posterior scleritis with amelanotic chorioidal mass initially diagnosed as intraocular tumor. The patient showed the features of nodular posterior scleritis without associated systemic disease. The case presented symptoms of severe eye pain, unilateral proptosis, hyperemia and dilatation of scleral, episcleral and conjunctival vessels. Diagnosis was made on the basis of B-scan ultrasonography. Differential diagnosis excluded melanoma malignum chorioideae, orbital cellulitis, Graves ophthalmopathy, orbital cellulitis, cavernous sinus thrombosis and carotid-cavernous fistula. The patient did not respond well to systemic steroids given in high doses and during slow tapering at the dosage of 30 mg prednisone once per day the symptom of uveal effusion syndrome occurred. After 10 months of steroid therapy the signs of disease like mild hyperemia and tenderness were still present. The adjunction of cyclosporin improved the disease and caused the remission.

Ceramide is not a signal for tumor necrosis factor-induced gene expression but does cause programmed cell death in human vascular endothelial cells.

Tumor necrosis factor (TNF) activates transcription of endothelial leukocyte adhesion molecule-1 (CD62E) in endothelial cells (ECs) through the binding to the gene promoter of the p50/p65 heterodimeric form of nuclear factor-kappa B (NF-kappa B) and of the N-terminal phosphorylated form of the ATF2/c-Jun transcription factor, which is phosphorylated by Jun N-terminal kinase (JNK). However, the intracellular signaling pathways that activate endothelial NF-kappa B and JNK in TNF-induced responses are unknown. In this study we have examined the role of a recently described TNF signaling pathway involving sphingomyelin activation to generate ceramide, a potential intracellular mediator. We find that concentrations of TNF that strongly activate NF-kappa B and JNK within 15 minutes do not produce either a measurable decline in sphingomyelin or a measurable generation of ceramide in cultured human umbilical vein ECs at any time examined. Stimulation of ECs with purified sphingomyelinase (SMase) enzyme causes a rapid 60% to 80% decrease in cellular sphingomyelin content and a large increase in ceramide. However, SMase treatment only minimally activates NF-kappa B, achieving levels that are insufficient to initiate gene transcription. Extracellular SMase does not have access to intracellular sphingomyelin, but treatment of ECs with membrane-permeant ceramide analogues still completely fails to activate NF-kappa B and only activates JNK at late times. Neither SMase nor ceramide analogues induce gene transcription or surface expression of endothelial leukocyte adhesion molecules that are readily induced by TNF. Strikingly, low concentrations of membrane-permeant ceramide cause programmed cell death in ECs, a finding not observed at any concentrations of TNF tested. We conclude that ceramide is not an important second messenger for TNF signaling of gene transcription in ECs but may be a second messenger for cell death in response to as-yet-unidentified signals.

[Angioid streaks in Grönblad-Strandberg syndrome]. / Pasma naczyniaste siatkówki w zespole Grönblad-Strandberga.

The authors present signs and symptoms in Grönblad-Strandberg syndrome and current opinions on therapeutic procedures in choroidal neovascularization where central vision is threatened. The publication includes a case report.

[Clinical evaluation of Uro-Vaxom in treatment of recurrent urinary tract infections in girls]. / Kliniczna ocena preparatu Uro-Vaxom w leczeniu nawracajacych zakazen ukladu moczowego u dziewczynek.

Uro-Vaxom was used in the treatment of recurrent urinary tract infections in 28 girls. Most of them (27/28) tolerated the drug very well, no side effects were observed. We stopped administration of the Uro-Vaxom in one girl during the first month of treatment because of vomiting. Uro-Vaxom efficiency was, therefore, evaluated in 27 girls. Uro-Vaxom was found to be a valuable drug, supplementing antibiotic therapy in recurrent urinary tract infections caused by E. coli.

Localization of azithromycin in Toxoplasma gondii-infected cells.

Agents effective against intracellular pathogens must enter infected cells, crossing vacuolar membranes surrounding the organisms and then penetrating into the microbe and localizing to the microbial target site. We have characterized these parameters for azithromycin entry into Toxoplasma gondii-infected Chinese hamster ovary cells and murine macrophage-like J774 cells. Azithromycin uptake into infected host cells was concentrative and was dependent upon proton gradients. Subcellular fractionation of azithromycin-loaded infected CHO cells demonstrated > 95% intracellular drug in host cell lysosomes and cytosol, with < 5% associated with the parasite. Uptake of azithromycin into the T. gondii vacuole increased if parasites were coated with antibody prior to internalization by murine J774 cells, conditions which result in the formation of acidified phagolysosomes. No redistribution or retention of azithromycin in the parasite was observed when drug efflux from antibiotic-loaded infected CHO cells was monitored. Azithromycin entry into extracellular T. gondii was concentrative, was temperature and pH dependent, and was not different when azithromycin-sensitive and -resistant parasites were compared. These results demonstrate that azithromycin concentrates primarily in acidified compartments in parasites and host cells. The high concentration of azithromycin within these compartments may not be biologically relevant to inhibition of intracellular parasite growth by this agent.

Tumor necrosis factor activates human endothelial cells through the p55 tumor necrosis factor receptor but the p75 receptor contributes to activation at low tumor necrosis factor concentration.

Tumor necrosis factor-alpha (TNF-alpha) interacts with two distinct membrane receptor proteins, p55 and p75, which are variably expressed on different cell types. We have examined the function of p55 and p75 on human endothelial cells (EC). Both receptor types are detected on cultured EC by FACS analysis. A mutagenized recombinant human TNF (R32W-TNF), which binds selectively to p55, is equipotent with human recombinant wild-type TNF (wt-TNF) in upregulating several different leukocyte adhesion molecules as well as class I major histocompatibility complex molecules. R32W-TNF also fully desensitizes EC to wt-TNF, as assessed by inhibition of re-induction of endothelial leukocyte adhesion molecule-1 (ELAM-1). At low wt-TNF concentrations, induction of ELAM-1 is partly inhibited by blocking monoclonal antibodies to either p55 or p75 and to a greater extent by a combination of both monoclonal antibodies. In contrast, ELAM-1 induction by R32W-TNF is only inhibited by anti-p55. We conclude that both TNF receptors (p55 and p75) can contribute to TNF-induced activation of EC, but that signaling through p55 is sufficient.

Elevated cyclic AMP inhibits endothelial cell synthesis and expression of TNF-induced endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1, but not intercellular adhesion molecule-1.

We have investigated the role of cAMP as a signal transducer for TNF-induction of leukocyte adhesion molecule expression in cultured human umbilical vein endothelial cells (EC). Forskolin, a stimulator of adenylate cyclase, either alone or in combination with isobutyl methylxanthine (IBMX), an inhibitor of phosphodiesterase, fails to induce expression of endothelial leukocyte adhesion molecule 1 (ELAM-1 or E-selectin), of vascular cell adhesion molecule 1 (VCAM-1) or of intercellular adhesion molecule 1 (ICAM-1 or CD54). Unexpectedly, this combination of cAMP-elevating drugs inhibits TNF induction of ELAM-1 and VCAM-1 but not ICAM-1 expression. Similar results were observed with the membrane-permeant cAMP mimetics 8 bromoadenosine 3':5' cyclic monophosphate (8Br-cAMP) and N(6)2'-O-dibutyryladenosine 3':5'-cyclic monophosphate. Inhibition was greater at lower TNF concentrations (< 10 U/ml), at higher 8 Br-cAMP concentrations (> 100 microM), and at early times (2 h). Forskolin plus IBMX selectively inhibits TNF-induced increases in ELAM-1 and VCAM-1 mRNA, indicating that the action of cAMP is to block synthesis of these molecules. TNF, through stimulation of prostaglandin synthesis, produces slight elevations in the levels of endothelial cAMP. However, these increases in cAMP appear too small compared to those induced by forskolin plus IBMX to inhibit adhesion molecule expression. Indeed, complete inhibition of the TNF-mediated rise in cAMP, achieved by blocking cyclooxygenase with indomethacin, does not alter ELAM-1 expression. We conclude that cAMP is neither an intracellular mediator nor a physiological regulator of TNF-induced adhesion molecule expression in EC. However, our findings suggest that pharmacological elevations of cAMP in EC, by inhibiting TNF-induced synthesis of ELAM-1 and VCAM-1, could serve to limit inflammation.

Laminin enhances binding of Toxoplasma gondii tachyzoites to J774 murine macrophage cells.

We investigated the effects of the extracellular matrix proteins laminin and fibronectin on the attachment of tachyzoites of Toxoplasma gondii to the murine macrophage cell line J774. Laminin but not fibronectin increased parasite attachment to J774 cells in a dose-dependent fashion. Cyclic YIGSR, a laminin-derived peptide which inhibits laminin binding to the 32/67-kDa laminin-binding protein on host cells, blocked the laminin-mediated enhancement of parasite attachment. An antiserum to the 32/67-kDa laminin-binding protein also inhibited binding of parasites to J774 cells. These results, in conjunction with our previous observations (G. C. Furtado, F. L. Collins, and K. A. Joiner, submitted for publication), demonstrate that tachyzoites bearing surface laminin bind to multiple laminin receptors in attaching to different target cells.

[Atypical form of phenylketonuria caused by lack of dihydrobiopterin synthetase activity]. / Nietypowa postac fenyloketonurii spowodowana brakiem aktywnosci syntetazy dihydrobiopterynowej.

A case of non-typical phenylketonuria produced by the inactivity of dihydrobiopterin synthetases is presented. Dihydrobiopterin synthetases are enzymes converting neopterin to biopterin. Presented case indicates a possibility of erroneous classification of hyperphenylalaninemia due to BH4 deficit, if the complete differential diagnosis is not performed. A complete differential diagnosis is necessary in all cases of hyperphenylalaninemia distinguished in neonates during screening tests.

The effect of soluble antigens from polyoma tumor and liver cells on stimulation of lymph nodes measured by incorporation of 14C-leucine.

The effect of solube antigens from polyoma tumor cells, liver antigens and PHA on lymph node cells from tumor bearers and on normal lymph node cells in CBA mice was studied. The stimulation index was calculated on the basis of incorporation of 14C-leucine in short-term cultures. The stimulation index was lower in lymphocytes derived from tumor bearers than those from normal donors. The blastoid responses to polyoma-associated antigens and PHA were similar, in contrast to liver-associated antigens. It was concluded that stimulation of liver antigens may be connected with different chemical structure, mainly of carbohydrate components.