Fabricating Optical-quality Glass Surfaces to Study Macrophage Fusion.

Visualizing the formation of multinucleated giant cells (MGCs) from living specimens has been challenging due to the fact that most live imaging techniques require propagation of light through glass, but on glass macrophage fusion is a rare event. This protocol presents the fabrication of several optical-quality glass surfaces where adsorption of compounds containing long-chain hydrocarbons transforms glass into a fusogenic surface. First, preparation of clean glass surfaces as starting material for surface modification is described.

Development of fusogenic glass surfaces that impart spatiotemporal control over macrophage fusion: Direct visualization of multinucleated giant cell formation.

Implantation of synthetic material, including vascular grafts, pacemakers, etc. results in the foreign body reaction and the formation of multinucleated giant cells (MGCs) at the exterior surface of the implant. Despite the long-standing premise that fusion of mononucleated macrophages results in the formation of MGCs, to date, no published study has shown fusion in context with living specimens.

Gold nanorod-incorporated gelatin-based conductive hydrogels for engineering cardiac tissue constructs.

Unlabelled: The development of advanced biomaterials is a crucial step to enhance the efficacy of tissue engineering strategies for treatment of myocardial infarction. Specific characteristics of biomaterials including electrical conductivity, mechanical robustness and structural integrity need to be further enhanced to promote the functionalities of cardiac cells. In this work, we fabricated UV-crosslinkable gold nanorod (GNR)-incorporated gelatin methacrylate (GelMA) hybrid hydrogels with enhanced material and biological properties for cardiac tissue engineering.

A three dimensional micropatterned tumor model for breast cancer cell migration studies.

Breast cancer cell invasion is a highly orchestrated process driven by a myriad of complex microenvironmental stimuli, making it difficult to isolate and assess the effects of biochemical or biophysical cues (i.e. tumor architecture, matrix stiffness) on disease progression.

Fibrinogen matrix deposited on the surface of biomaterials acts as a natural anti-adhesive coating.

Adsorption of fibrinogen on the luminal surface of biomaterials is a critical early event during the interaction of blood with implanted vascular graft prostheses which determines their thrombogenicity. We have recently identified a nanoscale process by which fibrinogen modifies the adhesive properties of various surfaces for platelets and leukocytes. In particular, adsorption of fibrinogen at low density promotes cell adhesion while its adsorption at high density results in the formation of an extensible multilayer matrix, which dramatically reduces cell adhesion.

Combined single cell AFM manipulation and TIRFM for probing the molecular stability of multilayer fibrinogen matrices.

Adsorption of fibrinogen on various surfaces produces a nanoscale multilayer matrix, which strongly reduces the adhesion of platelets and leukocytes with implications for hemostasis and blood compatibility of biomaterials. The nonadhesive properties of fibrinogen matrices are based on their extensibility, ensuing the inability to transduce strong mechanical forces via cellular integrins and resulting in weak intracellular signaling. In addition, reduced cell adhesion may arise from the weaker associations between fibrinogen molecules in the superficial layers of the matrix.

Chronic toxicity and carcinogenicity testing in the Sprague-Dawley rat of a prospective insect repellant (KBR 3023) using the dermal route of exposure.

The chronic toxicology and carcinogenic potential of 1-(1-methyl-propoxycarbonyl)-2-(2-hydroxyethyl)-piperidine (KBR 3023), a prospective new insect repellent intended for human use, was studied in rats using the dermal route of application. Relying upon the toxicology profile that emerged in the subchronic rat bioassay that was conducted using dermally applied dosages of 0, 80, 200, 500 and 1000 mg KBR 3023/kg body wt/day, it was determined, in concert with the Environmental Protection Agency (EPA), that dermally applied dosages of 0, 50, 100 or 200 mg KBR 3023/kg body wt/day would be used in the conduction of all definitive forms of subchronic, chronic, and lifetime descriptive testing performed with the chemical. Using this testing approach, the specific results of this 2-year study are as follows.

Carcinogenicity testing in the CD-1 mouse of a prospective insect repellent (KBR 3023) using the dermal route of exposure.

The carcinogenic potential of 1-(1-methyl-propoxycarbonyl)-2-(2-hydroxyethyl)-piperidine (KBR 3023), a prospective new insect repellent intended for human use, was studied in mice using the dermal route of application. Relying upon the toxicology profile that emerged in the subchronic rat bioassay that was conducted using dermally applied dosages of 0, 80, 200, 500, and 1000 mg KBR 3023/kg body weight per day, it was determined, in concert with the EPA, that dermally applied dosages of 0, 50, 100, or 200 mg KBR 3023/kg body weight per day would be used in the conduct of all definitive forms of subchronic, chronic, and lifetime descriptive testing performed with the chemical. Using this testing approach, the specific results of this 18-month study are as follows.

Comparative metabolism of ortho-phenylphenol in mouse, rat and man.

1. Ortho-phenylphenol (OPP) was well absorbed in the male B6C3F1 mouse, with 84 and 98% of the administered radioactivity recovered in the 0-48-h urine of animals administered a single oral dose of 15 or 800 mg/kg respectively. High absorption and rapid elimination were also seen in the female and male F344 rat with 86 and 89% respectively of a single oral dose (27-28 mg/kg) found in the urine in 24 h.

Urinary physiologic and chemical metabolic effects on the urothelial cytotoxicity and potential DNA adducts of o-phenylphenol in male rats.

ortho-Phenylphenol (OPP), a fungicide and antibacterial agent with food residues, is carcinogenic to rat bladder. The present studies provide information on changes in urinary composition and urinary metabolites, urothelial cytotoxicity and regenerative hyperplasia, and DNA adducts in male F344 rats fed OPP. An initial experiment evaluated dietary doses of 0, 1,000, 4,000, and 12,500 ppm OPP fed for 13 weeks.

Tributyl phosphate effects on urine and bladder epithelium in male Sprague-Dawley rats.

Tributyl phosphate (TBP) produces tumors of the bladder urothelium in rats at high doses (700 and 3000 ppm), with greater effects in males than in females. TBP does not produce tumors in mice and it is nongenotoxic. The dose response of TBP effects on urine and urothelium was evaluated in male Sprague-Dawley rats at 0, 200, 700, and 3000 ppm of the diet, 10 rats per group, for 10 weeks.

Comparative kinetic analysis of cholinesterase methods in rat and human erythrocytes and plasma.

A kinetic analysis of the substitution of 6,6'-dithiodinicotinic acid (DTNA) for 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) for the determination of rat and human erythrocyte acetylcholinesterase (AChE; EC 3.1.1.

Evidence of chemical stimulation of hepatic metabolism by an experimental acetanilide (FOE 5043) indirectly mediating reductions in circulating thyroid hormone levels in the male rat.

N-(4-Fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1,3, 4-thiadiazol-2-yl]oxy]acetamide (FOE 5043) is a new acetanilide-type herbicide undergoing regulatory testing. Previous work in this laboratory suggested that FOE 5043-induced reductions in serum thyroxine (T4) levels were mediated via an extrathyroidal site of action. The possibility that the alterations in circulating T4 levels were due to chemical induction of hepatic thyroid hormone metabolism was investigated.

Extrathyroidally mediated changes in circulating thyroid hormone concentrations in the male rat following administration of an experimental oxyacetamide (FOE 5043).

Evidence of increased hepatic metabolizing capacity coupled with reductions in serum thyroxine (T4) levels were noted in the rat during preliminary toxicity studies with FOE 5043, an oxyacetamide with herbicidal properties. These findings were consistent with reports in the literature suggesting that declines in T4 as a result of exposure to various classes of chemicals may be mediated extrathyroidally, such as through chemical induction of hepatic thyroid hormone metabolism. To examine this question with respect to FOE 5043, male rats were surgically thyroidectomized and provided thyroid hormone replacement therapy via implanted osmotic minipumps capable of maintaining a T4/triiodothyronine (T3) serum concentration for approximately 4 weeks at a level comparable to that of euthyroid controls.

Interlaboratory cholinesterase determinations and the effect on the results of statistical evaluation of cholinesterase inhibition.

Cholinesterase activity is often a key parameter in the regulatory assessment of cholinesterase-inhibiting agents such as organophosphorous and carbamate pesticides. Thus, the nature and characteristics of the methodology involved in the measurement of plasma (PChe), erythrocyte (R Che), and brain (BChe) cholinesterase activity takes on a heightened degree of importance. In this study an interlaboratory comparison of cholinesterase activity as determined by various laboratories was conducted in order to assess the influence that different methodologies may have on the results of statistical evaluation of cholinesterase inhibition.

Cardiovascular responsiveness to parathyroid hormone (PTH) and PTH-related protein in genetic hypertension.

Hypertension is often accompanied by abnormalities of calcium homeostasis, including hyperparathyroidism with reduced target organ responses to PTH in kidney and bone. Due to this association between PTH and hypertension and since PTH and the paracrine factor PTH-related protein (PTHrp) have both been shown to exert marked changes in cardiovascular activity, these actions of PTH and PTHrp were examined in spontaneously hypertensive rats (SHR) and in control normotensive Wistar-Kyoto rats (WKY). Fourteen-week-old SHR [systolic blood pressure (SBP), 201 +/- 4.

Evidence for pteridine regulation of lead-mediated inhibition of uroporphyrinogen and heme formation in rat bone marrow.

Uroporphyrin I (URO I) accumulation has been reported in the bone marrow of rats exposed to lead, suggesting a sensitivity of uroporphyrinogen III cosynthase (COSYN) to this heavy metal. Furthermore, it has been reported that a polyglutamated folate derivative may serve as a coenzyme for the catalytic action of hepatic uroporphyrinogen III cosynthase. These findings raised the question of whether depletion of polyglutamated folate could enhance the susceptibility of bone marrow COSYN to lead and potentially interfere with the formation of heme.

The effect of combined treatment with potassium dichromate and maleic acid on renal function in the rat.

Subthreshold doses of potassium dichromate (K2Cr2O7) have been shown to enhance or potentiate the nephrotoxic effects of mercuric chloride and citrinin. The mechanism of this effect is unknown. The purpose of this study was to examine the phenomenon further by investigating the interaction of K2Cr2O7 with maleic acid, a nephrotoxicant with an action though to be different from those above.

Effect in the rat of the interaction of dichloromaleic acid and carbon tetrachloride on renal and hepatic function.

Water purification generates a variety of chlorinated contaminants, one of which is dichloromaleic acid (DCMA). Exposure to this compound is likely to occur in combination with other drinking water pollutants, some of which are hepatotoxic. This study was designed to examine the interactive effects of carbon tetrachloride (CCl4), a known hepatotoxin, with DCMA on liver and kidney function in the Sprague-Dawley rat.

Alterations in the renal function of male and female rats exposed to maleic acid, dichloromaleic acid, and both compounds.

Maleic acid (MA), a known nephrotoxicant in experimental animals, and its chlorinated derivative dichloromaleic acid (DCMA) are present in urban drinking water supplies as by-products of the chlorination process. This study was designed to characterize the effects of simultaneous exposure of subtoxic doses of DCMA and MA on renal function in both sexes of the Sprague-Dawley rat. Urine was collected at 24-h intervals from rats housed individually in stainless steel metabolism cages.

Nosocomial hepatitis A infection in a paediatric intensive care unit.

Seven members of staff in a paediatric intensive care unit and two of their relatives developed hepatitis A over a period of five days. A 13 year old boy who was incontinent of faeces prior to his death, was presumed to be the source of infection. Two hundred and sixty seven other members of staff underwent serological testing and were given prophylactic pooled gamma globulin.

Extraction and isolation by high performance liquid chromatography of uroporphyrin and coproporphyrin isomers from biological tissues.

A simple, rapid procedure has been developed for extraction of uroporphyrin and coproporphyrin isomers from biological tissues. The recoveries of known standards of uroporphyrin I and III and coproporphyrin I and III were performed from liver, kidney, testis, and bone marrow of the rat. The extracted samples were analyzed by high performance liquid chromatography.

Reversal of sulfamerazine inhibition of rat hepatic uroporphyrinogen synthesis by folic acid.

The ability of rat hepatic uroporphyrinogen cosynthase to direct formation of uroporphyrinogen III and the synthesis of uroporphyrinogen in vitro was impaired by sulfamerazine. Inhibition was reversed by the addition of folic acid. Administration of a single, oral dose (1 g/kg) of sulfamerazine to rats was associated with elevated levels of hepatic uroporphyrin I isomer.