Carlos E. Nasjleti

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.

Healing after tooth reimplantation in monkeys. A radioautographic study.

The purpose of this study was to examine radioautographically the dynamics of tissue changes during healing after reimplantation of maxilliary incisors in adult rhesus monkeys. The period selected for the study was 1 day to 4 months. The study revealed that a new attachment will be restored after tooth reimplantation. Epithelial tissues start to proliferate immediately after reimplantation; this proliferation reaches its peak in 3 days. After 7 days a new junctional epithelium is re-established. Connective tissue proliferation reaches its peak in 7 days and starts mainly from the supracrestal connective tissue and the bone marrow spaces. The interface is undetectable after 7 days, being replaced by young connective tissue which re-establishes the continuity of the periodontal membrane and the supracrestal connective tissue. Orientation and maturation of the fibers are not observed until 4 months after reimplantation. Changes toward root resorption and ankylosis can be seen as early as 14 days after reimplantation.

Differential diagnosis of adult male black and white populations.

Abstract No Abstract Available. From the Dental Research Institute and Veterans Administration Hospital, University of Michigan, Ann Arbor, Michigan.

Interruption of the Arterial Inferior Alveolar Flow and its Effects on Mandibular Collateral Circulation and Dental Tissues

The interruption of circulation through the inferior alveolar artery was followed by the establishment of a fast retrograde blood flow through the vessel. The mental artery and the mandibular branch of the sublingual artery were the main vessels to contribute to that flow. No histopathologic changes were found in the experimental hemimandibles; however, temporary regressive changes were found in the dental pulps of molars.

Histopathologic findings in temporomandibular joints of aged individuals

Twenty-four TMJs from well preserved 62- to 97-year-old human cadavers, 12 men and 12 women, were used in this study. The TMJs were routinely processed to identify (1) the histologic and histopathologic changes present in the articulations and (2) the components of the joint most frequently affected by these changes. The most significant histopathologic findings were (1) intense fibrocartilaginous proliferations of the condylar head and articular eminence linings, (2) neovascularization or myxomatoid degenerative changes in articular disks, and (3) proliferation of synovial villi, subsynovial tissue, and muscular fibers. The components of the joint most frequently affected were (1) the condylar head (30.4%), (2) the articular disk (21.7%), (3) the synovial lining (13%), (4) the articular eminence (8.6%), and (5) the lining of the articular fossa (4.3%). Five joints were considered to be within normal histologic limits, and one joint was excluded from the study because of metastatic malignancy.

Replantation of Mature Teeth Without Endodontics in Monkeys

The purpose of this study was to evaluate the histologic response after replantation of mature, developed teeth without endodontic treatment in monkeys. To serve as experimental controls, the other replanted teeth received endodontic treatment. No significant differences were noted in the rate and quality of periodontal tissues healing between the endodontically and the nonendodontically treated teeth in monkeys sacrificed at 5, 7, and 14 days, and at 1, 2, and 3 months after replantation. However, specimens obtained at 4, 6, 9, and 12 months showed that teeth replanted without endodontics developed periapical complications, whereas endodontically treated teeth did not.

Chromosome polyploidization in human leukocyte cultures treated with streptonigrin and cyclophosphamide.

Treatment of cultured human peripheral blood leukocytes with streptonigrin or cyclophosphamide resulted in morphologic chromosomal changes, as well as polyploid and endoreduplicated mitoses. Polyploidy was present in 11% of cells treated with streptonigrin and in 15% of cells treated with cyclophosphamide. These findings, together with recent data showing polyploidization in normal human leukocytes induced in vivo and in vitro with chemotherapeutic agents and ionizing radiations, suggest that polyploidy and endoreduplication of chromosomes as reported in acute leukemia, might to a large extent be the result of concomitantly administered therapy.

Long-term results after intentional tooth reimplantation in monkeys

The purpose of this study was to evaluate histologically the long-term response to intentional tooth reimplantation in six rhesus monkeys. The study revealed that cervical and apical root resorption is a universal complication after tooth reimplantation and that arrested areas of resorption will show repair by deposition of cementum. A highly cellular periodontal membrane usually will develop. Periodontal fibers will reattach to reparative bone and cementum but seldom regain functional orientation. Partial or complete ankylosis may result. A further complication is progressive undermining resorption of the ankylosed teeth. Long-term studies are mandatory to evaluate the response to intentional tooth reimplantation.

Connective Tissue Response to Periodontal Dressings

The effects of three periodontal dressings (Coe-Pak, PPC, Perio Putty) upon subcutaneous tissues in 26 Sprague-Dawley rats were investigated. The three dressings, and a control (Teflon), were placed into polyethylene tubes. Two tubes per animal were implanted on either side of the dorsal midline area. After 14 days the specimens were retrieved and prepared for histological examination. Three methods of scoring were utilized for evaluation. First, a system evaluating the overall number of inflammatory cells, connective tissue capsule thickness, and the vascular changes produced; second, an inflammatory cell count, the Inflammatory Index (I.I.), computing the inflammatory cells in a particular field of view for each material; and third, a Reaction Spread Index (R.S.I.) comparing the distance of the spread of the inflammatory reaction into the connective tissues. Statistical analysis of the data was carried out utilizing the Chi-square test and analysis of variance. While the three scoring systems utilized did result in some comparative variation in reactions, the overall order of decreasing severity was always PPC, Coe-Pak, Perio Putty, and Teflon.

Revascularization of the Periodontium After Tooth Grafting in Monkeys

In replanted and homo transplanted teeth a vascular network developed in the blood clot between the two parts of the torn periodontium, which allowed the grafted ligament to regain its vascularity. When dentoalveolar ankylosis developed, the periodontal vasculature was split into a number of vascular clusters. In homotransplants, a definite cellular immunologic response by the host was absent. An acrylic radicular obturator was used.