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In the title compound, C8H5NS3, the dihedral angle between the heterocyclic ring and the phenyl ring is 2.62 (5)°. In the extended structure, aromatic π–π stacking between the 1,4,2-dithiazole-5-thione moiety and the phenyl ring is observed [centroid–centroid distances = 3.717 (6) and 3.712 (6) Å]. The almost planar molecules arrange themselves in parallel chains of head-to-tail molecules oriented by a network of weak C—H...S contacts close to the sum of their van der Waals radii within the chains. All the hydrogen atoms participate in hydrogen-bonding interactions with the sulfur and nitrogen atoms of adjacent molecules. C=S...S contacts between the chains that are significantly shorter than the sum of their van der Waals radii also impact the overall packing.

Case Presentation: We describe a case of epipericardial fat necrosis. Discussion: Epipericardial fat necrosis is an inflammatory condition in which the pericardial fat pad necrotizes resulting in surrounding inflammation. This condition mimics more ominous pathology in clinical presentation and radiographic findings. Management is supportive with oral analgesics.

Case Presentation: We describe a case of epipericardial fat necrosis.Discussion: Epipericardial fat necrosis is an inflammatory condition in which the pericardial fat pad necrotizes resulting in surrounding inflammation. This condition mimics more ominous pathology in clinical presentation and radiographic findings. Management is supportive with oral analgesics.

Recent studies of the sieving of serum albumin in the rat kidney using a two-photon microscope suggested that the glomerular sieving coefficient (GSC) of albumin is 0.034, much higher than earlier micropuncture determinations. In the present study, we critically evaluated the use of the two-photon microscope to measure the GSC of albumin in the Munich-Wistar rat in vivo. The albumin GSC averaged 0.004 (SD 0.004), n = 34 glomeruli, when determined with a Zeiss two-photon microscope system and 0.002 (SD 0.002), n = 5, when determined with an Olympus two-photon microscope system. These values are close to the lower limit of detection of GSC, which we estimate to be ~0.001-0.003. We identified several factors that were likely responsible for the higher albumin GSCs reported earlier using two-photon microscopy. These include animal conditions (i.e., low glomerular filtration rate) and failure to recognize the role of out-of-focus fluorescence in contaminating the fluorescence signal from the urinary space of Bowman's capsule. We observed that hypothermia plus dehydration or a low blood pressure led to an increased albumin GSC. High levels of illumination (high laser outputs) resulted in a falsely elevated albumin GSC. Use of external, instead of internal, photodetectors resulted in an exaggerated albumin GSC because of greater collection of out-of-focus fluorescence. In conclusion, the albumin concentration in the glomerular filtrate of the normal rat, determined by two-photon microscopy, is exceedingly low (5-10 mg/dl). glomerular permeability; multiphoton microscopy; rat kidney

Many aspects of the glomerular filtration of macromolecules remain controversial, including the location of the major filtration barrier, the effects of electrical charge, and the reason the filtration barrier does not clog. We examined these issues in anesthetized Necturus maculosus, using fluorescently labeled probes and a two-photon microscope. With the high resolution of this system and the extraordinary width (~3.5 [micro]m) of the glomerular basement membrane (GBM) in this salamander, we were able to visualize fluorescent molecules in the GBM in vivo. GBM/plasma concentration ratios for myoglobin, ovalbumin, and serum albumin did not differ from that of inulin, indicating that the GBM does not discriminate among these molecules. The GBM/ plasma concentration ratios for fluoresceinated dextran 500 and 2,000 kDa were significantly below that of inulin. Glomerular sieving coefficients (GSCs) for various macromolecules decreased as molecular mass increased, and the GSCs for bovine or human serum albumin were extremely low. The effect of electrical charge on filterability of a macromolecule was also examined. The GSCs for native (anionic) and neutral human serum albumin were not significantly different, nor did GSCs for anionic and neutral dextran 40 kDa differ, indicating that charge has no detectable effect on filterability of these macromolecules. These studies indicate that the main filtration barrier to albumin is the podocyte slit diaphragm. Electron microscopic studies revealed many cell processes within the GBM. Macromolecules that penetrated the GBM were taken up by mesangial cells and endothelial cells, suggesting that these cells help to prevent clogging of the filter. amphibian kidney; glomerular filtration barrier; two-photon microscopy

Understanding molecular mechanisms of pathophysiology and disease processes requires the development of new methods for studying proteins in animal tissues and organs. Here, we describe a method for adenoviral-mediated gene transfer into tubule or endothelial cells of the rat kidney. The left kidney of an anesthetized rat was exposed and the lumens of superficial proximal tubules or vascular welling points were microinfused, usually for 20 min. The microinfusion solution contained adenovirus with a cDNA construct of either 1) Xenopus laevis actin depolymerizing factor/cofilin [XAC; wt-green fluorescent protein (GFP)], 2) actin-GFP, or 3) GFP. Sudan black-stained castor oil, injected into nearby tubules, allowed us to localize the microinfused structures for subsequent visualization. Two days later, the rat was anesthetized and the kidneys were fixed for tissue imaging or the left kidney was observed in vivo using two-photon microscopy. Expression of GFP and GFP-chimeric proteins was clearly seen in epithelial cells of the injected proximal tubules and the expressed proteins were localized similarly to their endogenously expressed counterparts. Only a minority of the cells in the vitally exposed regions, however, expressed these proteins. Endothelial cells also expressed XAC-GFP after injection of the virus cDNA construct into vascular welling points. An advantage of the proximal tubule and vascular micropuncture approaches is that only minute amounts of virus are required to achieve protein expression in vivo. This micropuncture approach to gene transfer of the virus cDNA construct and intravital two-photon microscopy should be applicable to study of the behavior of any fluorescently tagged protein in the kidney and shows promise in studying renal physiology and pathophysiology. actin; actin depolymerizing factor; adenovirus; green fluorescent protein; intravital microscopy

Sulfonefluorescein (SF) is a fluorescent organic anion secreted by kidney proximal tubules. The purposes of this study were 1) to quantify accumulation of SF in normal and cystic rat kidneys in vivo and 2) to test whether SF accumulation could be used as a marker for cysts derived from proximal tubules. Male Munich-Wistar rats, normal Han:SPRD rats, and heterozygous Han:SPRD rats with autosomal-dominant polycystic kidney disease were anesthetized with Inactin and solutions containing SF were administered by constant intravenous infusion. In Munich-Wistar rats, SF fluorescence in the urinary space of Bowman's capsule averaged 0.15 [+ or -] 0.04 (n = 17) times that of glomerular capillary plasma, consistent with extensive plasma protein binding of SF. In normal Han:SPRD rats, steady-state cell cytoplasm SF fluorescence in proximal tubule and distal tubule cells averaged, respectively, 2.7 [+ or -] 1.4 (n = 99 tubules) and 0.2 [+ or -] 0.2 (n = 17) times that of peritubular capillary plasma. No punctate SF fluorescence was seen in proximal tubule cell cytoplasm. Probenecid reduced proximal tubule cell SF fluorescence to 0.64 [+ or -] 0.40 (n = 64) times that of plasma. Ureteral obstruction decreased the proximal tubule cell-to-lumen SF fluorescence gradient, suggesting that tubule fluid flow normally sweeps away secreted SF. In cystic kidneys, cysts derived from proximal tubules could be identified by their uptake of SF, but cell uptake was patchy. We conclude that in vivo two-photon microscopy is a powerful tool for quantifying glomerular and tubular handling of SF, and SF can be used to identify proximal tubule-derived cysts. organic anion secretion; glomerulus; polycystic kidney disease; two-photon microscopy

Optical microscopy, when applied to living animals, provides a powerful means of studying cell biology in the most physiologically relevant setting. The ability of two-photon microscopy to collect optical sections deep into biological tissues has opened up the field of intravital microscopy to high-resolution studies of the brain, lens, skin, and tumors. Here we present examples of the way in which two-photon microscopy can be applied to intravital studies of kidney physiology. Because the kidney is easily externalized without compromising its function, microscopy can be used to evaluate various aspects of renal function in vivo. These include cell vitality and apoptosis, fluid transport, receptor-mediated endocytosis, blood flow, and leukocyte trafficking. Efficient two-photon excitation of multiple fluorophores permits comparison of multiple probes and simultaneous characterization of multiple parameters and yields spectral information that is crucial to the interpretation of images containing uncharacterized autofluorescence. The studies described here demonstrate the way in which two-photon microscopy can provide a level of resolution previously unattainable in intravital microscopy, enabling kinetic analyses and physiological studies of the organs of living animals with subcellular resolution. fluorescence; multiphoton; in vivo