Benign Cephalic Histiocytosis: A Case Report

Histiocytic skin disorders are usually classified as either Langerhans' cell histiocytosis (LCH) or non LCH, based on the pathology. Benign cephalic histiocytosis (BCH) is a rare type of non-Langerhans histiocytitic disorder and is characterized by self-healing multiple small eruptions of yellow to red-brown papules on the face and upper trunk. Histologic features of this disorder show dermal proliferation of histiocytes that have intracytoplasmic comma-shaped bodies, coated vesicles and desmosome-like structures. In this study, we report on a 7-month-old boy who contained small yellow-red papules on his face that spread to his upper trunk. The clinical and histologic features in this patient were consistent with BCH.

Morphological Adaptive Responses of Gastric Parietal and Colonic Surface Epithelial Cells to Chronic Changes in Dietary Potassium / 대한해부학회지

Potassium (K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. It has been established that chronic potassium depletion is associated with a remarkable hypertrophy of the collecting duct of the kidney. But, there is no morphological studies regarding the stomach and distal colon during the chronic changes of potassium diet. Electron microscopy was performed to observe the morphological alterations of the stomach and distal colon in response to chronic changes of potassium diet in rat. Electron microscopy of normal parietal cells revealed the presences of many mitochondia, tubulovesicles, and short basal cytoplasmic processes and microvilli in the intracellular canaliculi. In potasium-depleted parietal cells, mito-chondria were increased in size and number, and tubulovesicles almost disappeared, and microvilli in the intracellular canaliculi were increased in number and length, and short basal cytoplasmic processes were also increased in size and number. Parietal cells of potassium-loading after restriction were found to be almost normal. Two types of surface columnar epithelial cells were present in normal distal colon. Type I cells had many mitochondria and abundant coated vesicles in the supranuclear region. Type II cells had moderate amount of mitochondria and relatively fewer coated vesicles. In comparison with normal, potasium-depleted surface columnar epithelial cells had more abundant and larger mitochondria and more numerous and longer (1.4~1.6 times than normal) microvilli. Surface columnar epithelial cells of potassium-loading after restriction were recovered almost to normal. These results suggest that gastric parietal cells and surface columnar epithelial cells of distal colon adapt through morphological changes to preserve potassium balance during chronic changes of potassium diet.

Aspectos farmacotécnicos dos lipossomas: produçäo, caracterizaçäo e estabilidade / Pharmaceutical aspects of liposomes: manufacture, characterization and stability

O tamanho, a carga e a rigidez dos lipossomas dependem da composição da bicamada lipídica e do método empregado na preparação das vesículas. De acordo com suas características, lipossomas podem permanecer na circulação sangüínea por um curto espaço de tempo (alguns minutos) ou por muitas horas (alguns dias) caso sejam estáveis e não sejam reconhecidos por macrófagos. Para sua utilização como veiculadores de fármacos, os lipossomas devem ser preparados de forma a apresentar reprodutibilidade e homogeneidade na produção lote-a-lote, na estabilidade e nas características de liberação do fármaco. Nesta revisão, estão descritos os métodos mais comumente empregados na preparação das vesículas e são discutidos os principais aspectos relacionados à estabilidade e aos processos industriais

Caveolae a new subcellular transport organelle

Recent advances have allowed the identification and characterization of well defined vesicular subcellular organelles involved in multiple basic cellular physiological processes, with demonstrated clinical relevance. Among these, three particular subcellular organelles have received special attention based on their proven and postulated participation in the sorting and targeting of small-and large-molecular weight molecules during exocytosis and endocytosis, and in cell signaling and transduction events. These have characteristic proteinaceous coat structures that allows their classification accordingly, into what has been described as clathrin coated vesicles and COP-coated vesicles and caveolae. In this review article a brief description of clathrin-coated vesicles and COP-coated vesicles is presented. Caveolae (CAV), in turn, constitute a novel subcellular organelle that has received special attention based on its proven and postulated participation in transcytosis, potocytosis, and in cell signaling and transduction events. In this review of the literature a more extensive discussion is presented of CAV. In this context the article discusses the structural features of caveolae, its constituent protein caveolin(s), the functional aspects of this new organelle, and its postulated clinical relevance

Effect of urea on biomimetic aggregates

The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities.

Vesicular transport: implications for cell polarity

In polarized cells intracellular sorting of plasma membrane proteins occurs to a large extent at the trans-Golgi network, giving rise to vesicles destined for distinct plasma membrane domains. This review discusses the several pathways, both direct and indirect, which lead to protein incorporation into the correct cell surface, as well as the mechanisms involved. Proteins contain signals which direct their incorporation into the distinct vesicles destined for plasma membrane microdomains. Specific coat proteins are involved in vesicle assembly and are likely to play a role in the generation of discrete vesicle populations. Molecules involved in vesicle docking and fusion may also add specificity to the targeting process.

Calcium- and zinc-binding proteins in intracellular transport

The complex mechanism of intracellular transport is regulated by free calcium in different manners. Calcium binding proteins regulate several aspects of the vesicle fusion mechanism mediated by NSF (N-ethylmaleimide sensitive fusion factor). At least in some regulated exocytosis, calcium-binding proteins are the trigger for fusion downstream of NSF, Still, calcium-binding proteins, such as annexins, may be part of a different fusion mechanism mediating some specific transport steps or working in parallel to the NSF-dependent fusion process. Calcium is not the only ion necessary for the function of factors involved in vesicular transport. A zinc requirement has been also proposed. One of the zinc-dependent factors is probably a protein with a cysteine-rich region that coordinates zinc and binds phorbol esters. Although protein kinase C is the more prominent family of proteins carrying this domain, the factor necessary for transport does not appear to function as a kinase.

Mechanism of formation of post Golgi vesicles from TGN membranes: Arf-dependent coat assembly and PKC-regulated vesicle scission

We have developed an experimental system that utilizes purified Golgi fractions obtained from virus infected infected MDCK cells to reproduce in vitro the process of vesicle generation in the trans Golgi network, an important site for the sorting of proteins addressed to the plasma membrane, secretory vesicles, or lysosomes. Using an integrated biochemical and electron microscopic approach, we have shown that the formation of post Golgi vesicles carrying proteins destined to both plasma membrane domains of epithelial cells requires the activation of an ArF-like GTP-binding protein that serves to promote the assembly of the protein coat necessary to deform the donor membrane and generate a vesicle. The formation of the post Golgi vesicles also requires the participation of a Golgi membrane-associated Protein Kinase C, but not its phosphorylating activity. Other authors have shown that this is also the case for the PKC activation of the enzyme phospholipase D, which generates phosphatidic acid from phosphatidyl choline and may be involved in remodeling of membranes. We have been able to dissect the process of post Golgi vesicle generation into two sequential stages, one of coat assembly and bud formation, and a subsequent one of vesicle scission. The first stage can occur at 20 degrees C and requires the activation of the Arf protein necessary for coat assembly. The second stage does not require nucleotides or an energy supply, but requires cytosolic proteins, and in particular, an NEM sensitive membrane scission promoting activity that operates only at a higher temperature of incubation. Because various PKC inhibitors blocked vesicle scission without preventing bud formation, we propose that the PKC is required for the activation of a PLD in the TGN, which leads to remodeling of the donor membrane and the severing of connections between the emerging vesicles and the membranes.

An Ultrastructural Study on the Structural Development of the Cardiac Ganglion in the Human Fetuses

The development of the cardiac ganglion was studied by electron microscopy in human fetuses ranging from 30mm to 270mm crown rump length. At 40mm fetus, the cardiac ganglia were observed in the adventitia of both the aorta and pulmonary artery, superior aspect of the left and right atrium, and interatrial septum. The cardiac ganglia were comprised of clusters of undifferentiated cells, neuroblasts, and unmyelinated nerve fibers. The ganglia were small and uncapsulated until 70mm fetus. At 70mm fetus, the cardic ganglia consisted of neuroblasts, satellite cells, and unmyelinated nerve fibers. Each ganglion was ensheathed in a connective tissue capsule. The cytoplasm of neuroblast contained Nissl bodies, mitochondria, coated vesicles, extensive Golgicomplex, and rough endoplasmic reticulum. Synaptic contacts between the cholinergic preganglionic axon and dendrites of postganglionic neuron were first observed. At 100mm fetus, the cardiac ganglia consisted of small clusters of ganglion cells and dendrites, together with supporting elements and blood vessels. During next prenatal stage from 170mm fetus, the ganglion cells were large and each contained a large nucleus with one or more nucleoli. The cytoplasm of ganglion cells contained much rough endoplasmic reticulum and extensive Golgi complex. Cholinergic preganglionic axons were numerous and interposed between the satellite cells. Adrenergic axons were rarely observed. A great number of synaptic junctions between the cholinergic preganglionic axon terminals and the dendrites of postganglinic neuron were found, and a few axosomatic synapses were also observed. Adrenergic nerve terminals did not seem to be involved in the synaptic transmission. The cardiac ganglion cells of the human fetal heart were innervated only by cholinergic nerve.

A Case of Benign Cephalic Histiocytosis / 대한피부과학회지

A 18-month-old girl was seen because of an yellowish brown papular eruptions on the face, earlobes and neck of one year duration. A skin biopsy specimen revealed circumscribed cellular infiltrates composed of predorninantly pleornorphic histiocytes. Electron microscopy of biopsy material disclosed numerous worm like particles and coated vescles in limited area of the cell cytoplasm, consistent with the findinga described in benign cephalic histiocytosis. After six months of her first visit, the individual papules became flattened.