Seong S. Han

The secretion processes in mucous and serous secretory cells of the rat sublingual gland

The discharge processes of secretory substances in mucous acinar cells and serous demilune cells were studied in the sublingual gland of nonstimulated rats and rats stimulated to secrete by simultaneous injections of isoproterenol and pilocarpine. In the acinar cells of both stimulated and nonstimulated glands, mucous granules, masses of fused granules and mucus, as a result of the rupture of the granule membranes, discharged into the lumen through breaks formed in the apical cell membrane. The complete discharge of mucus, which occurred in the stimulated glands, left large spaces in the cytoplasm of the acinar cells. These spaces were lined with small vesicles which appeared to form a limiting membrane. The secretory granule discharge was observed in the demilune cells of nonstimulated glands but not in stimulated glands. These serous granules discharged by establishing a continuity between their membranes and the apical cell membrane.

An enzyme histochemical study of the effect of various concentrations of formocresol on connective tissues

Abstract A histochemical profile of selected enzyme activities has been assessed in connective tissue cells of polyvinyl sponge implants in the absence or presence of various dilutions of formocresol. The effects of formocresol are more severe among cells receiving the higher concentrations. Little difference is noted between the full concentration of formocresol and a 1 5 dilution in terms of initial effects of tissue fixation. Thus, it is concluded that a 1 5 dilution may be as effective as the full concentration and, at the same time, may provide a faster recovery from the cytotoxic effects of formocresol.

Effects of varying concentrations of formocresol on RNA synthesis of connective tissues in sponge implants

Summary By means of quantitative radioautography, this study evaluated the synthesis of RNA by connective tissue cells subjected to varying concentrations of formocresol (FC). As indicated by the incorporation of uridine-H 3 , two pieces of polyvinyl alcohol sponge were implanted in the subcutis of the right and left dorsal scapular regions of Syrian hamsters and were left for 30 days. Then 50 μl of FC in full concentration and in dilutions of 1/5, 1/25, or 1/125 was injected into the sponge implant on one side, whereas the implant on the contralateral side was given the same amount of vehicle alone. The animals were sacrificed at various daily intervals. Thirty minutes or 3 hours prior to sacrifice they were injected with uridine-H 3 (10 μc per gram body weight). Implants were embedded in epoxy resin in a routine manner, and sections 1 μ thick were made on an ultramicrotome. The sections were coated with Kodak NTB-3 liquid emulsion. An evaluation of the labeling index in various sponges indicated a complete fixation of the tissue by the full concentration, whereas at a 1/5 concentration a similar obliteration of RNA synthesis was observed during the second week of the postoperative period. At lower concentrations, there is no sustained effect after the third day. The relative grain number of functioning cells was high throughout the series and was clearly higher in sponges receiving lower concentrations of FC, suggesting a stimulated synthesis of RNA. Similarly elevated counts are noted in control sponges during the first few days after injection of the vehicle. It is concluded that FC, at 1/5 of the usual concentration, might be an equally effective and possibly less damaging pulpotomy agent as compared to the traditional preparation.

Radioautographic and Electron-Microscopic Evidence of Rapid Uptake of Antigen by Lymphocytes

Iodine-125-labeled ferritin molecules were detected by radioautography in the sinuses of the rat popliteal lymph node shortly after injection into the foot pad; they appeared to be taken up by macrophages and phagocytic reticular cells. Electron microscopic examination of the same tissue also revealed ferritin molecules within small lymphocytes as early as 5 minutes after injection. The antigen appeared to be taken up by the process of pinocytosis and was distributed throughout the cytoplasm and nucleus. While the number of ferritin molecules observed in the lymphocyte was much less than that taken into the inacrophage, the observation is significant in understanding the role lymphocytes play during the early phase of antibody response.

A study of the histopathology of gingival hyperplasia in mental patients receiving sodium diphenylhydantoinate

T he remarkable effect of sodium diphenylhydantoinate (commonly called d-Dilantin or Epanutin) on grand ma1 seizures has promoted extensive use of the drug in many related mental cases.l While most side actions can be controlled by other pharmacologic agents, the gingival hyperplasia produced by Dilantin persists, regardless of parallel treatments. Numerous att,empts with antihistamines and vitamin C rendered no positive results, and the literature still reflect,s a state of conflict.2-s For details on the historical survey, the reader is referred to the excellent reviews by Reader9 and by Gardner and co11eagues.1” Insofar as the microscopic appearance of the lesion is concerned, the appearance of the epithelium, the proliferation of underlying connective tissue elements, and the infiltration of inflammatory cells have been described. However, many of the histopathologic observations made in the past have been supplementary to clinical observations.lOp I1 In this article we will attempt to describe a comprehensive picture of histopathologic changes in forty-eight mental patients who have been under regular treatment with sodium diphenylhydantoinate.

Effect of parasympathetic denervation on acetylcholine levels in the rat parotid gland. Is there an extraneuronal pool of acetylcholine

Parasympathetic denervation of the rat parotid gland by avulsion of the auriculotemporal nerve caused a marked and lasting decrease in gland weight. Parasympathectomy did not change the levels of choline in the gland but decreased by 60% the levels of acetylcholine (ACh) ten days after surgery and 65% at 28 days. It is puzzling that relatively high levels of ACh remained after parasympathetic denervation. The presence of additional cholinergic nerves that innervate the gland, or pass through it en route to other structures may account for some of the remaining ACh. Also, Schwann cells from denervated nerves might have contributed to some of the ACh. The existence of an extraneuronal source of ACh is considered.

Studies on Hypoxia: II. Autoradiographic Quantitation of Proline-3H Incorporation by Connective Tissue Cells of the Neonatal Hamster

Quantitative evaluation of autoradiographic grains from anoxia-treated and control neonatal hamster indicated that anoxia impairs collagen synthesis and significantly suppresses the incorporation of proline-sH in the odontoblast, fibroblast, and osteoblast by 24 hours after the insult. However, the rapid and apparently total recovery of the dental and paradental connective tissue cells suggests that anomalies of dentition, heretofore attributed to brief spells of anoxia at birth, may not be due to such a hypoxic insult during the perinatal period.

Effects of actinomycin D on the salivary glands of the rat

EFFECTS OF ACTINOZlYCIN D ON THE SALIVARY GLANDS OF THE RAT Heun T . Jhee and Seong S . Hen Younsei University School of Medicine, Seoul, Rorea and The University of Michigan School of Dentistry, Ann Arbor, Michigan, (Received 13 August 1964) SINCE the isolation of actinomycin D from Streptomycea parvallus (1) in 1954 its potent cytostatic effects have been widely recognized and numerous reports have already appeared describing the effects of it and related compounds on embryonic tissues (2-5), various tumors (6-11) and other normal tissues (12-14) Meanwhile, the chemical mechanisms of actinomycin in inducing cytostatic effects have been clarified to a large extent and experiments have proven that the drug can be used as an excellent analytic tool for studies of the biosynthesis of proteins, especially of the role played by the messenger RNA (m-RNA) in the process (15-27) . A survey of these articles and others illuminates the following : (1) m-RNA is produced in the nucleus by the DNA-dependent RNA polymerases ; (2) m-RNA is important in the maintenance of the functional and structural integrity of polyribosomes which are primarily dependent upon the continued availability of m-RNA, the turnover of which is relatively fast and (3) the production of the m-RNA can be inhibited effectively by actinomycin D which specifically carbines with DNA, resulting in the blockade of DNA-dependent RNA polymerase activity . With respect to the digestive glands synthesizing enzymes for secretion ; an insult imposed by the administration of actinomycin D would seriously effect the functioning of the gland which in turn would be reflected in its structure . The present study is aimed at describing the cytological changes observed in the parotid gland of the rat following a eublethal dose of actinomycin D. Materials and Methods Twenty-eight adult male Sprague-Dawley rata were used . Of these, twenty-

Effects of 5-Fluorouracil on Exocrine Glands I. Gland Weights in Mice Receiving Synthetic Polynucleotides

Summary Body weights and weights of major salivary glands and pancreas of mice given sublethal doses of 5-FUR were studied after pilocarpine or poly A:U injection. Body weights showed a significant decrease during the first 5 days after 5-FUR alone, while in the same period the glandular weights increased in all 4 organs. Injections of pilocarpine prior to sacrifice abolished the increase in glandular weights in salivary glands, but the pancreas failed to respond. This increase in organ weight was thought to be due to the inability of the organs to release synthesized secretory products. An injection of poly A:U 24 hr prior to sacrifice produced a uniform release of secretory products during the recovery phase in all of the organs studied. Such effect was notably absent on day 5 when the 5-FUR effect was at a maxium. It is concluded that the introduction of synthetic poly A:U might improve the recovery processes following nucleotide insult, as well as trigger release mechanisms in a manner which is different from that of pilocarpine.

An Electron Microscopic Autoradiographic Study of Proline Incorporation by Mouse Lingual Epithelium

SummaryMouse lingual epithelium incorporates significant amounts of L-proline-2, 3-H3 one hour after intraperitoneal injection of the tritiated amino acid. All viable cell strata incorporated approximately equal amounts of proline as assessed by autoradiographic techniques. Grain counts at 30 minutes, 1 hour, 4 hours and 24 hours, the four time periods studied, indicated a progressive incorporation of proline up to 4 hours following injection. Preferential incorporation of proline into any one cell structure or group of structures was not observed. Keratohyalin granules (KHGs) demonstrated incorporated proline; however, usually only one silver grain appeared over each granule, and, based on grain counts, the amount of proline incorporated by KHGs appeared slightly less than the general labeling observed in KHG-containing cells. This finding supports recent biochemical studies which have indicated a considerably lower proline content of keratohyalin than had previously been reported. Significant proline incorporation into the epithelial basal lamina was not observed during the 24 hours of this study. Thus, while recent recombination experiments have conclusively demonstrated that epithelial basal cells synthesize considerable quantities of basal lamina in a 24 hour period; it would appear that epithelial basal cells contribute little to a formed, intact basal lamina. This finding lends credence to the concept of a long basal lamina turnover time.