The Synthesis of Keratinosomes During Epidermal Wound Healing

Employing suction-induced subepidermal blisters as a model of epidermal wound healing, the formation of keratinosomes in a differentiating epidermis has been studied. Keratinosomes appear at 24 hr after wounding. They are more fully developed at 36 hr, preceding the formation of the horny layer at 48 hr. At that time a horny layer becomes visible and keratinosomes can be seen both intra- and extra-cellularly at the granular horny cell interface

Effect of hemicholinium-3 on choline distribution in vivo in the canine caudate nucleus,

The effect of hemicholinium (HC-3) on choline distribution was studied in vivo in the subcellular fractions of the canine caudate nucleus. Both HC-3 and choline were given intraventricularly to locally anesthetized, decamethonium-paralyzed dogs maintained on artificial ventilation. At various time intervals after intraventricular injection of methyl-14C-choline alone and in various HC-3/methyl-14C-choline ratios, the animals were sacrificed by air embolus and the caudate was removed and subjected to subcellular fractionation. It was found that methyl-14C-choline accumulated primarily in the microsomal (Mic) and the nerve ending, mitochondria, lysosome (NEML) fractions. There was greater accumulation at 4 hr than at 1 hr. The combined injection of HC-3 and methyl-14C-choline in ratios of 10, 100, 500 and 2500 progressively increased the uptake of choline by the subcellular elements; an extract of the water-soluble components of fraction NEML showed that HC-3 reduced the c choline to acetylcholine. On the other hand, HC-3 increased the labeling of phosphorylcholine and, particularly, of cytidine diphosphocholine. The levels of free choline in the caudate were not affected by HC-3.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32766/1/0000137.pd

A fine structural study of divalent cation-mediated epithelial union with connective tissue in human oral mucosa

Following incubation in an isotonic saline solution containing 20 mM EDTA, human oral mucosa may be separated into its epithelial and connective tissue components. Ultrastructural study of the separated tissues reveals that the plane of separation is through the lamina lucida. Hemidesmosomal structure is altered by the separation process: the peripheral density is absent but a fine, generally filamentous material remains associated with the outer membrane leaflet of the hemidesmosome. Desmosome structure is not altered. An intact lamina densa remains attached to the connective tissue fragment. Oral mucosa incubated in EDTA-saline containing calcium, or its return to a divalent cation-supplemented medium after treatment with EDTA, prevents separation. By maintaining the structural integrity of the hemidesmosome, divalent cations appear to play a principal role in uniting oral mucosal epithelium to the lamina propria.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49659/1/1001330406_ftp.pd

The effect of diethanolamine on hepatic and renal phospholipid metabolism in the rat

DEA inhibited the in vitro synthesis of both phosphatidyl choline and phosphatidyl ethanolamine in liver tissue. In each case the K1 was approximately 3 m DEA. DEA inhibited the formation of phosphatidyl choline competitively, and produced a mixed type of inhibition for the synthesis of phosphatidyl ethanolamine. Administration of a single dose of 250 mg/kg DEA failed to produce inhibition of synthesis, but 330 mg/kg/day caused significant inhibition when given repeatedly. The most notable reduction of choline and ethanolamine incorporation occurred in the liver. The synthesis of ethnolamine phosphoglycerides declined to 27% of the control value after 1 week of DEA administration; no further reduction was seen during the remainder of the 3-week dosing regimen. Choline incorporation fell to 82% of the control value after 1 week, and to 47% and 41% after 2 and 3 weeks of DEA administration, respectively. The incorporation of these endogenous bases in renal tissue was also decreased. Ethanolamine phosphoglyceride synthesis declined steadily throughout the dosing regimen reaching a level 41% of control. Choline incorporation declined to 71% or control by the end of the third week. The kinetics of synthesis of the phospholipid derivatives of choline, ethanolamine, and DEA proved that the former two compounds were synthesized at a faster rate and in greater quantities. They were also catabolized at a slightly faster rate than the derivatives of DEA. The biological half-life of the phospholipid derivatives of DEA is longer than that of similar derivatives of choline and ethanolamine. This may favor accumulation of the DEA-containing phospholipid during chronic exposure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23609/1/0000571.pd

Demonstration of Pemphigus Antibodies on the Cell Surface of Murine Epidermal Cell Monolayers and their Internalization

The pathogenic effects of pemphigus vulgaris (PV) antibodies on epidermal cells can be demonstrated both in vitro using skin organ culture or primary epidermal cell cultures (PECC) and in vivo by passive transfer of PV antibodies into neonatal BALB/c mice. Although PV antibodies have been localized on the epidermal cell surface by several techniques, little is known about the fate of these autoantibodies subsequent to their surface binding. We have examined this, using murine PECC which express pemphigus antigen on their surface, and followed the fate of the bound antibody molecules. Forty-eight-hour PECC were incubated at 37°C with PV antibodies for 20 min and then with horseradish peroxidase-labelled antihuman IgG. This was considered time 0. The monolayers were fixed with glutaraldehyde after 0, 0.5, 1, 3, 6, 18, and 24 h incubation at 37°C and then processed for electron microscopy. At time 0 hour, PV antibodies is detected bound evenly along the surface of keratinocytes. Within 30 min, the bound PV antibodies becomes clustered, internalized into submembranous vesicles via surface pits, and eventually fused with lysosomes. Widening of the intercellular spaces was also seen in PECC treated with PV antibodies within the first 24 h. PECC treated with normal human IgG in parallel cultures showed no such surface binding, internalization, or cell-cell detachment. Treatment with cytochalasin-D and/or colchicine did not affect the internalization of the PV antibodies, but fusion with lysosomes was not seen in treated cultures.These findings suggest that PV antibodies binds a surface antigen and the complex is internalized and fused with lysosomes in a process that may have pathophysiologic relevance

The Subcellular Distribution of Acyltransferases which Catalyze the Synthesis of Phosphoglycerides

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65213/1/j.1432-1033.1969.tb00602.x.pd