Secretion of alpha-amylase from parotid lobules of young and old rats

The rate of release of a secretory enzyme, alpha-amylase, from the parotid lobules of 2 and 24 month old rats has been compared to determine whether the secretory activity of the cells change during aging. Upon incubation in the presence of a secretogogue, isoproterenol (10(-5) M), about the same proportions of the glandular alpha-amylase are released at about the same rate from these lobules. The isoproterenol-stimulated release of the enzyme is inhibited nearly completely by preincubating the lobules with propranolol (10(-5) M) in both age groups, indicating that the enzyme secretion occurs through the stimulation of beta-receptors. When viewed in the electron microscope, the cell membranes bordering the secretory lumen in isoproterenol-incubated lobules reveal festooned appearances which suggest that the enzyme release occurs by means of exocytosis. These observations indicate that the ability of the parotid cells to release secretory products through the beta-receptor mediation does not significantly change with increasing age.

Further evolution of the grasping technique for tendon repair

Refinement of the modified Kessler tendon-suturing technique is described. The lateral longitudinal limbs of the modified Kessler suture are shifted to a location adjacent to one another in the core of the tendon slightly palmar to the tendon's central axis. This does not compromise the immediate tensile strength of the repair, and eliminates compression of the central portion of the tendon between the two lateral longitudinal limbs of the suture. It also gives rotational freedom to the repair even after the suture is tied, allowing adjustment of the rotational alignment of the tendon ends. These effects are demonstrated using fresh human cadaver digital flexor tendons.

Seasonal variation of saponins, sucurose and monosaccharides in cultivated ginseng roots

Yield of methanolic extract of fresh roots of Ginseng harvested in winter was found to be more than two-fold grater than from roots collected in summer; this remarkable increase is mainly due to the large increase of sucrose in roots in winter. On the other hand, biologically active dammarane-saponins in the roots increase in summer. These results indicate that roots should be harvested in summer for the production of high quality Ginseng extracts.

Age-related changes in the cellular level of amylase and protein synthesis in the rat parotid gland

Age-related changes in the cellular content of secretory proteins and protein synthesis were studied in parotid glands of rats of various ages. The secretory protein content (determined by measuring the level of alpha-amylase activity) and the synthesis of proteins (assayed by the rate of incorporation of 3H-leucine into acid-insoluble proteins) decline with increasing age. Morphological and radioautographic studies of the gland indicate that the decline in protein synthesis is due to the reduction in the ability of secretory cells to synthesize proteins.

DNA sequences mediating class switching in alpha-immunoglobulins

Immunoglobulin class switching involves specific DNA rearrangements of the gene segments coding for heavy chain constant regions (CH) during B lymphocyte differentiation. In two different cases of C mu to C alpha switching examined here (T15 and M603) and one taken from the literature (MC101), three different sites on the 5' side of C mu and three different sites on the 5' side of C alpha are joined together in the process of CH switching. The sequences surrounding the three germ-line C alpha sites of recombination are highly conserved blocks of 30 nucleotides that may serve as recognition sequences for CH switching to the C alpha gene. This putative recognition sequence is repeated 17 times in approximately 1400 nucleotides of the germ-line Calpha 5' flanking sequence. The lack of homology between this C alpha sequence and sequences reported for the C gamma 1 and C gamma 2b switch sites suggests that heavy chain switching is mediated by class-specific recognition sequences and, presumably, class-specific regulatory mechanisms. In addition, it appears that in one example (MC101) CH switching progressed from C mu to C alpha to C gamma 1. This switching pathway may present difficulties for the simple deletional model of CH switching.

Fine structure of cell types in an ameloblastoma

An unusually large and old ameloblastoma, which revealed a diverse histological appearance, was studied by light and electron microscopy. In the tumor, the epithelial component formed several patterns in the collagenous stroma. The epithelial islands, consisting of tall columnar cells surrounding the inner core of stellate cells, mimicked the cells of the inner enamel epithelium and stellate reticulum, respectively, of the normal enamel organ. The ultrastructural appearances of the columnar cells, however, were only similar to those which are seen in undifferentiated preameloblasts. Areas of squamous metaplasia were present, and these squamous cells were structurally similar to the cells at the base of the oral epithelium. Some epithelial cells containing numerous lipid granules and mitochondria formed a network of cords. The connective tissue stroma was made up of fibroblast-like cells which appear to be metabolically active. In addition, multinucleated giant cells were present in the connective tissue stroma near the epithelial component.

Cyclophosphamide-induced abnormalities in the incisors of the rat

A single injection of 75 mg/kg cyclophosphamide caused gross dental abnormalities in rats. Broken, malformed, overgrown, and "extra" incisors developed several weeks after drug treatment. Radioautographic investigations show no unusual features in the morphology or labeling with H3-thymidine in the odontogenic cells. The results suggest that the cytotoxic effect of the drug is a temporary one which induces a residual alteration of tooth growth.

Cytochemical characterization of the myoepithelial cells in palatine glands

Myoepithelial cells of rat and mouse palatine glands are similar in fine structural appearance to those of other exocrine glands and smooth muscle cells. Myoepithelial cells reveal fibrils, and vesicular structures comparable to pinocytic or surface vesicles of smooth muscle cells. Lanthanum-impregnated preparations of the gland reveal that many of these vesicle-like structures are, in fact, invaginations of the plasma membrane and are continuous with the extracellular space. Observations on glandular tissue incubated for the demonstration of ATPase and adenylate cyclase have indicated that a high level of activity of these two enzymes is localized in the plasma membrane of the myoepithelial cells facing the acinar cells, and in vesicular structures along this membrane. The possibility that these enzyme activities are related to contractility of myoepithelial cells is discussed.

The localization of thiamine pyrophosphatase activity in the acinar cells of stimulated and non-stimulated sublingual glands of the rat

The distribution of thiamine pyrophosphatase (TPPase) activity in the acinar cells of the rat sublingual gland has been studied at various stages of the secretory cycle following stimulated secretion. The rats were stimulated to secrete by an intraperitoneal injection of isoproterenol and pilocarpine. In non-stimulated glands, TPPase activity is detected mainly in 3--4 cisternae at the inner concave side of the Golgi complex and in some adjacent condensing vacuoles as in other cells. In the acinar cells 1 to 2 h after stimulation, however, reaction product for the same enzyme activity is detected in the cisternae at the outer aspect, as well as the inner aspect, of the Golgi complex and even in the cisternae of the endoplasmic reticulum (ER). About 4 h after stimulation, TPPase activity becomes concentrated in 3--4 cisternae at the inner concave side of the Golgi complex as in the acinar cells under non-stimulated conditions. Morphological observations of the acinar cells 1 to 2 h after the stimulation have indicated that the reorganization of the Golgi complex and ER is a major event which occurs at this stage. It is possible that this cellular event is related to the occurrence of TPPase activity in those sites which normally show negative reaction in non-stimulated state.

Massive edema of the ovary

Ovarian edema is a newly recognized clinicopathologic entity. A case of massive ovarian edema is presented in which a huge abdominal mass was considered to be an ovarian cyst roentgenographically and clinically. However, ultrasound revealed the mass to be solid. Five previously reported cases in which ovarian edema simulated a fibroma are reviewed.

The cytochemical localization of adenylate cyclase activity in mucous and serous cells of the salivary gland

The present study was undertaken to localize adenylate cyclase activity in salivary glands by cytochemical means. For the study, serous parotid glands and mixed sublingual glands of the rat were used. Pieces of the fixed glands were incubated with adenosine triphosphate (ATP) or adenylyl-imidodiphosphate (AMP-PNP) as substrate: inorganic pyrophosphate or PNP liberated upon the action of adenylate cyclase on the substrates is precipitated by lead ions at their sites of production. In both glands, the reaction product was detected along the myoepithelial cell membranes in contact with secretory cells, indicating that a high level of adenylate cyclase activity occurs in association with these cell membranes. The association with a high level of the enzyme activity might be related to the contractile nature of myoepithelial cells which are supposed to aid secretory cells in discharging secretion products. A high level of adenylate cyclase activity was also detected associated with serous secretory cells (acinar cells of the parotid gland and demilune cells of the sublingual gland), but not with mucous secretory cells. In serous cells, deposits of reaction product were localized along the extracellular space of the apical cell membrane bordering the lumen. This is the portion of the cell membrane which fuses with the granule membranes during secretion. Since the granule membranes are not associated with a detectable level of adenylate cyclase activity, it appears that the enzyme activity becomes activated or associated with the granule membranes as they become part of the cell membrane by fusion. The association with a high level of adenylate cyclase activity appears to be related to the ability of the membrane to fuse with other membranes. It is likely, since the luminal membrane of mucous cells which does not fuse with mucous granule membranes during secretion is not associated with a detectable enzyme activity.