Lanthanum Nitrate Tracer Research Articles

Location and chemical composition of semi-permeable layer of forage seeds

The presence of the semi-permeable layer is determined in Roegneria nutans (Keng.) Keng, Achnatherum inebrians (Hance.) Keng, Hordeum vulgare var. nudum Hook. f., Triticale, Festuca sinensis Keng., and Bromus inermis Leyss. using the lanthanum nitrate tracer method, transmission electron microscopy and energy dispersive X-ray analysis. It was an amorphous membranous structure firmly attached on the external portion of the seed coat. The diversified chemical composition of the semi-permeable layer of the species studied is also analyzed by histochemical staining. R. nutans, A. inebrians, H. vulgare var. nudum, and Triticale were found to contain lipids in the semi-permeable layer. F. sinensis had pectin whereas B. inermis has cellulose in the said layer. DOI: http://dx.doi.org/10.3329/bjb.v42i1.15802 Bangladesh J. Bot. 42(1): 23-29, 2013 (June)

PROTECTIVE EFFECTS OF GLUCAGON-LIKE PEPTIDE-1 VIA CAMP/PKA/RHO DEPENDENT PATHWAY ON CARDIAC MICROVESSELS INJURY IN DIABETES MELLITUS

ObjectivesGlucagon-like peptide-1 (GLP-1) was a hormone predominately synthesised and secreted by intestinal L-cells. Pharmacological modulation of the GLP-1 had emerged as an important treatment target for diabetes mellitus. In addition...

Effect of Electromagnetic Pulse Exposure on Brain Micro Vascular Permeability in Rats

To observe the effect of electromagnetic pulse (EMP) exposure on cerebral micro vascular permeability in rats. The whole-body of male Sprague-Dawley rats were exposed or sham exposed to 200 pulses or 400 pulses (1 Hz) of EMP at 200 kV/m. At 0.5, 1, 3, 6, and 12 h after EMP exposure, the permeability of cerebral micro vascular was detected by transmission electron microscopy and immunohistochemistry using lanthanum nitrate and endogenous albumin as vascular tracers, respectively. The lanthanum nitrate tracer was limited to the micro vascular lumen with no lanthanum nitrate or albumin tracer extravasation in control rat brain. After EMP exposure, the lanthanum nitrate ions reached the tight junction, basal lamina and pericapillary tissue. Similarly, the albumin immunopositive staining was identified in pericapillary tissue. The changes in brain micro vascular permeability were transient, the leakage of micro vascular vessels appeared at 1 h, and reached its peak at 3 h, and nearly recovered at 12 h, after EMP exposure. In addition, the leakage of micro vascular was more obvious after exposure of EMP at 400 pulses than after exposure of EMP at 200 pulses. Exposure to 200 and 400 pulses (1 Hz) of EMP at 200 kV/m can increase cerebral micro vascular permeability in rats, which is recoverable.

Early cellular and ultrastructural response of the mouse urinary bladder urothelium to ischemia.

An experimental ischemic model of mouse urinary bladder was developed to study urothelium permeability and changes in cell ultrastructure. The bladder permeability barrier response to experimental ischemia (30-120 min) was investigated by means of indigo carmine dye, trypan blue and lanthanum nitrate tracer, which were used as quantitative and qualitative indicators of urothelial integrity. Changes to the urothelium were studied by light microscopy, and by scanning and transmission electron microscopy. It was established that ischemia primarily induces breakdown of the blood-urine permeability barrier by disruption of the tight junctions. It causes focal interruption of the contacts between the cells, which is followed by detachment and desquamation of viable urothelial cells. Urothelial damage occurs as funnel-shaped wounds, which can extend into the lamina propria. They are proportional to the duration of ischemia and to the extent of reperfusion induced. Desquamated cells in the bladder lumen, when exposed to hypertonic and toxic urine, gradually become irreversibly changed.

Internalization of gap junctions between neuron and glial cell and formation of annular lamellar bodies in Chinese leech Whitmania pigra.

This paper reveals the formation of annular lamellar body (ALB) in the ganglion of leech by means of in situ fixation and the lanthanum nitrate tracer technique. This formation involves both wrapping and internalization of the gap junctions between glial processes themselves, as well as between neuron and glial process. The results indicate that there is probably an active process of internalization of membrane structures involving gap junctions between neuron and glial cell in the central nervous system in leech. The functions of ALB are discussed.

The permeability of the primary decidual zone in the rat uterus: an ultrastructural tracer and freeze-fracture study.

The rat primary decidual zone (PDZ) is a transitory avascular region of transformed fibroblasts surrounding the implanting embryo. Studies using fluorescein-labeled tracers have shown that the PDZ is selectively permeable to macromolecules, permeability decreasing with increasing molecular weight. In the present study we investigated the morphologic basis of the permeability barrier. Horseradish peroxidase (HRP) or HRP-labeled immunoglobulin G (IgG-HRP) was administered i.v. to rats on Day 7 of pregnancy, and the animals were killed 30 min to 2 h later. The reaction product of HRP was the same density in uterine blood vessels as in the intercellular spaces of the endometrium and PDZ at 30 min and 1 h after administration. Two hours after administration, the reaction product of IgG-HRP was dense in uterine blood vessels, much less dense in the interstitial spaces of the endometrium, and was not detected in the PDZ. There was an abrupt change in the density of the IgG-HRP reaction product at the intercellular clefts between endothelial cells, where cellular junctions were observed in control tissue. This suggests that the passage of large macromolecules from blood to the implantation chamber is limited initially by cellular junctions between capillary endothelial cells. The exclusion of IgG-HRP from the PDZ indicates that an additional barrier(s) to macromolecules in this region. Lanthanum nitrate tracer was uniformly present throughout the intercellular spaces of the PDZ except at tight junctions between decidual cells. Freeze-fracture replicas of the PDZ showed tight junctions that varied from single strands to interconnected networks of strands oriented mainly parallel to the long axis of the PDZ. Some strands were discontinuous. The tight junctions between decidual cells appear to be functionally discontinuous because HRP readily penetrated the PDZ, but such junctions may retard larger macromolecules such as IgG-HRP. The biological significance of the permeability barrier of the PDZ is discussed.

Lanthanum and freeze-fracture studies of retinal pigment epithelial cell junctions in the streptozotocin diabetic rat.

The blood-retinal barrier breaks down early in diabetes and previous morphological studies suggest that the retinal pigment epithelium (RPE) is the site of this defect. In the present study the electron microscope lanthanum nitrate tracer technique has been used to study RPE cell permeability in the streptozotocin diabetic rat retina. The freeze-fracture technique has been used to study RPE cell tight junction structure as permeability increases. In the lanthanum experiments, RPE cell permeability is normal in control rats and in diabetic rats 3 weeks after the injections. After 8 or 16 weeks of diabetes, however, the RPE cell layer no longer forms a barrier to the tracer and electron dense material is present in the subretinal space, in the apical and basal regions of the RPE cell junctions and intracellularly within the RPE. Freeze-fracture studies of tight junctions during this period show (1) an increase in the complexity of the tight junction network due to an increase in anastomoses between the tight junctions; (2) a change in membrane fracturing properties such that the tight junctional intra-membrane particles adhering to the E-face grooves are more numerous than in the control junctions; (3) no change in the number or size of the tight and gap junctional elements. These results suggest that the blood-retinal barrier breakdown in the diabetic RPE is due to alteration of plasma membrane permeability rather than to a loss of tight junctions.

The demonstration of complex gap junctions between the cells of the enamel organ with lanthanum nitrate

During enamel maturation the cells of the enamel organ are characterized by the presence of numerous mitochondria, coated vesicles, and microvilli suggesting that their function might be the transport of substances from the vascular compartment into the underlying enamel. Another prominent feature of the papillary cells is the presence of extensive intercellular contacts usually described as tight junctions. These areas of apparent membrane fusion occur between large exopthytic cytoplasmic processes and the indented surfaces of adjacent cells. Mitochondria are frequently observed to be in close relation to these junctions. Utilizing the method of prestaining with uranyl acetate and the lanthanum nitrate tracer technique it is now established that these junctions are of the gap variety. Thus the papillary layer contains intercellular junctions which are morphologically equivalent to those junctions believed to be responsible for intercellular ionic coupling. The demonstration of gap junctions provides evidence that a direct cytoplasmic route for the movement of ions or small metabolites does exist within the enamel organ.