Gershom Zajicek

FIBROBLAST CELL KINETICS IN THE PERIODONTAL LIGAMENT OF THE MOUSE

Twelve male mice were injected intraperitoneally with tritiated thymidine. Six were sacrificed after 1 hr and six after 7 days. The right manibular incisors were dissected, cut sagittally and dipped in liquid emulsion. In the exposed and stained slides, observation was restricted to the lingual side of the periodontal ligament. Cells were evaluated sagittally from the basal tooth end up to the distance of 5 mm and up to the depth of 100 μm in the direction of socket wall. Cell and grain count was evaluated separately in 100 × 10 μm rectangles, creating a two‐dimensional array onto which the periodontal ligament was mapped.

Growth rate analysis of lung metastases from histologically benign giant cell tumor of Bone

A growth rate analysis of lung metastaws of benign gaint cell tumor (GCT) Of Bone, Histologically Indistinguishable from the Primary benign tumor, is presented. The doubling time (DT) was 186 days in the first 13 months of growth, and 465 days in the last 4 months. These Dts are much longer than DT of lung metastases of any other tumors, and have a good correlation with a long survival time. Backward extrapolation showed that the lung metastases began to develop years before the primary tumor was diagnosed and treated. If this can be confirmed in a larger number of patients, it could be concluded that there will be no indication for amputation as a treatment for benign GCT whether or not lung metastases are present. The growth rate analysis supports the concept that these metastases might represent a benign process, and as such are a unique histologic and clinical phenomenon.

Effect of misoprostol and cimetidine on gastric cell labeling index

The effect of misoprostol and cimetidine on gastric cell turnover was studied. Endoscopic biopsy specimens of fundic and antral mucosa were obtained from duodenal ulcer patients before and after 4 wk of therapy with cimetidine 1.2 g/day or misoprostol 800 micrograms/day. Biopsy specimens were incubated with [3H]thymidine. Glandular column length and number of labeled cells were determined after autoradiography. There was no significant difference in column length of antral or fundic glands before or after therapy with cimetidine and misoprostol. The number of antral and fundic labeled cells was significantly decreased after misoprostol treatment (3.6 +/- 0.3 and 4.6 +/- 0.4, mean +/- SE), as opposed to their respective number before therapy (6.9 +/- 0.5 and 8.3 +/- 0.8) (p less than 0.01). On the other hand, after treatment with cimetidine, the number of antral and fundic labeled cells was significantly higher (11.8 +/- 0.9 and 7.5 +/- 1.0, respectively) as compared with their number before therapy (5.7 +/- 0.5 and 5.6 +/- 0.6, respectively). The decreased gastric cell turnover induced by misoprostol indicates that the trophic effect of prostanoids on gastric mucosa is not due to an increase in cellular kinetics. The increased gastric cell turnover induced by cimetidine may contribute to its therapeutic effect in peptic ulcer disease.

Role of Attrition and Occlusal Contact in the Physiology of the Rat Incisor: X. The Part Played by the Periodontal Ligament in the Eruptive Process

Removal of the proliferating base of the rat incisor did not influence the rate of eruption which responded to changes in impediment to eruption in a fashion similar to that for control teeth. It is the periodontal ligament rather than the proliferating cells that is responsible for tooth eruption. The elements of the periodontal ligament apparently responsible for tooth movement are the mature fibroblasts.

The intestinal proliferon.

Abstract The intestinal mucosa consists of several rapidly proliferating cell populations. These may be divided according to their function into two classes: (1) parenchyma: or epithelial cells; and (2) supporting cell populations including fibrocytes and vascular endothelial cells. The kinetics of all the cells in the villus are highly co-ordinated. It is postulated that at the pericryptal progenitor region where the cells originate, they are assembled into complex functional units denominated herewith as proliferons. The proliferon consists of four basic elements; parenchyma, connective tissue, blood vessels and nerve fibers. It starts its existence in the pericryptal lamina propria where the proliferating epithelia and fibroblasts receive their own capillary buds and special nerve supply. The displacement of the whole complex towards the villus tip is accompanied by a gradual elongation of the central villus artery. As the proliferon approaches the villus tip its supporting cell populations are catabolized while the epithelium is sloughed off into the lumen. This model has been previously called upon to describe the kinetics of rodent incisor tooth cell populations.

Turnover and Migration of Meibomian Gland Cells in Rats’ Eyelids

Purpose: The object of this study is to determine the velocity and migration course of meibomian gland cells. Materials and Methods: Twenty-seven adult rats weighing about 200 g were injected intraperitoneally with a single dose of 0.5 µCi [3H]-thymidine/g body weight. Three rats were sacrificed 1 h after injection and 3 rats each on days 3, 6, 9, 12, 15, 18, 21 and 28 after injection. The eyes and eyelids were removed in one piece, fixed in formalin, embedded in paraffin and cut into 5-µm-thick vertical sections along the pupillary-optic nerve axis. The sections were dipped in liquid autoradiographic emulsion, exposed for 3 weeks, and stained with HE. Meibomian glands were scanned in the lower eyelid of the left eye using an ocular micrometer grid. In each scan the basement membrane of each acinus served as a point of origin. Along the entire gland two parameters were noted for each nucleus with three grains or more: the distance from the basement membrane (Y) and grain count. Results: This study demonstrates for the first time the exact timing and direction of meibomian gland cell migration. We have shown that the cells migrate from the basement membrane to the center of the acinus at an average rate of 0.62 ± 0.11 µm/day. Cell generation time was an average of 4.1 days. Conclusions: The stem cells of meibomian glands lie at the circumference of each acinus. These cells migrate synchronously with a constant velocity towards the center of the acinus, and are secreted as sebaceous material.

Prophylactic administration of topical glutamine enhances the capability of the rat colon to resist inflammatory damage

Glutamine is an important nutrient for the GI tract and has been shown to exert a protective effect on the bowel. Nonetheless, in the context of IBD, data demonstrating a therapeutic role for glutamine has been inconclusive. IBD is associated with oxidative stress caused by reactive oxygen species. We aimed to investigate the effect of topical glutamine administration in rats before or after induction of colitis by trinitrobenzenosulfonic acid. In study I glutamine enemas were given beginning 2 days before or on the same day of induction of colitis. Inflammation severity was assessed by macroscopic and microscopic score and tissue myeloperoxidase activity. In study II glutamine enemas were given for 3 days without induction of colitis: mitotic index and colonic crypt length were measured, as well as water-soluble low molecular weight antioxidants and energy-rich phosphate levels (by HPLC). Results showed that glutamine significantly decreased indexes of inflammation when administered before induction of colitis. Glutamine caused an increase in the mitotic index and the levels of water-soluble low molecular weight antioxidants and energy-rich phosphates. We conclude that glutamine exerts a beneficial effect only when administered before induction of colitis, by increasing the resistance of the colonic tissue to inflammatory injury. This effect is probably mediated by increasing the antioxidant capacity and energy level of the tissue.

Role of Attrition and Occlusal Contact in the Physiology of the Rat Incisor: IX. Impeded and Unimpeded Eruption in Lathyritic Rats

In the rat, the administration of a lathyrogenic agent reduced both impeded and unimpeded eruption rates of incisors. Unimpeded eruption rates were greater than impeded eruption rates. The general eruption pattern in the experimental rats was, however, similar to that in the control rats. Thus, eruption was possible even in rats with a lathyrogenically impaired periodontal ligament.

Kinetics of the inner enamel epithelium in the adult rat incisor during accelerated eruption.

Inner enamel epithelial (IEE) cell production was compared in accelerated and normal eruption (control). Each group consisting of thirty rats received 1 μCi/g tritiated thymidine. The animals were sacrificed at short time intervals up to 14 hr after injection. The excised incisors were cut mid‐sagittally and processed autoradiographically.

The streaming of the submandibular gland II: parenchyma and stroma advance at the same velocity

Abstract Thirty young male rats aged 7 weeks, weighing 200 g, were injected with 18.5 kBq g−1 (0.5 μCi g−1) body weight tritiated thymidine [3H]TdR (specific activity 185 GBq). The rats were then killed in groups of five, at the following times: 1 hour, and 14, 30, 60, 90, and 120 days. Autoradiograms of sections through the submandibular gland were prepared, and the location of labelled cells in tubular and acinar cross sections was recorded. The nuclear content of each cross section was defined as its ‘class’. In this numbering system, narrow tubuli, e.g. intercalated ducts are of low class, and wider tubuli, e.g. striated ducts, of high class. One hour after labelling most labelled tubular cells were found in low class cross sections, i.e. intercalated ducts and narrow granular ducts. Striated ducts were not labelled. From then onward labelled cells entered wider tubuli, e.g. striated ducts. The advancing labelled epithelium was accompanied by labelled stroma. Both cell types traversed 0.089 classes per day. In acini, labelled cells advanced in the oposite direction, starting from acinar cross sections of high class and ending in class‐1 cross sections.