Morphological study of periodontal tissues in the initial stage of periodontal disease. Part 2. Analysis of morphological measurement and status of periodontal disease

The morphological characteristics of periodontal tissue in periodontal disease have been interpreted differently by a number of clinical observers. Many have reported that the malposition and functional malocclusion of teeth is injurious to the periodontium. We reported in Part I that a system for evaluating periodontal status was developed for the diagnosis and management of the interproximal area at the initial stage of bone resorption. The patient group consisted of 36 adults, from 21 to 55 years of age. The severity score represented the calculated loss of periodontal support tissues: loss of alveolar bone, evaluated roentgenologically, bone level and pattern in vertical and horizontal form, periodontal pocket and gingival inflammation. Because poor oral hygiene and other factors caused swelling by gingival inflammation, we obtained study specimens from patients with chronic periodontal disease after a few tooth brushing instructions, and scalings during initial therapy in order to detect initial and established pathological changes in periodontal tissue. The purpose of this study was to clarify the relationship between periodontal disease status and morphological diagnostic indicators and different degrees of harmony and disharmony in the lower jaw. In all age groups the average percentage of bone loss and intraosseous defects tended to be higher in the groups categorized as Type III and Type F, and in the area that showed a very deep concave Spee curve to the occlusal plane in Pattern D. We considered that these morphological characteristics might be of secondary importance for diagnosis. Oral local factors were the primary extrinsic factor in the pathogenesis of horizontal and vertical interproximal bone absorption in the area of the premolars and molars.     

Image analysis of the distribution of turnover rate in the stratum corneum

Background/aims: A common method to evaluate turnover rate in the stratum corneum is to measure the change in fluorescence intensity with time after dyeing the stratum corneum with fluorescent pigments. If these changes in fluorescence over time are carefully observed, the rate of decline in fluorescence intensity differs among different small areas on the skin surface. A possible relationship between these differences and dry skin has been reported. The purpose of this research was to develop a method for analyzing turnover rate in the stratum corneum in each small area on the surface of the skin as well as to investigate the variations in the inconsistencies of turnover rate. Methods: The stratum corneum at six body regions (forehead, cheek, forearm, opisthenar, back and lower leg) was dyed with dansyl chloride (DC), and the change in fluorescence intensity over time was imaged with a highly sensitive television camera through special filters. Then, the fluorescent distribution in the images was analyzed to measure the change in fluorescence intensity with time among the small areas. Also, the decline in fluorescence intensity observed was categorized using specific characteristics into six different types. Results: By attaching a filter to an ultraviolet (UV) light source in order to transmit light at the excitation wavelength and a filter to the camera lens to transmit light at the wavelength of DC fluorescence, we could image the low intensity fluorescent light from the DC without interference from the UV light exciting the DC. The characteristics of the variation in the decline in fluorescence intensity were categorized into six patterns. Type I: pattern showing a uniform decline in fluorescence intensity. Type II: pattern showing sporadic areas where fluorescence intensity declines quickly. Type III: pattern showing relatively large areas where fluorescence intensity declines slowly. Type IV: pattern showing sporadic areas of fluorescence intensity, matched with locations of keratotic plugs. Type V: pattern showing sporadic fluorescent areas, not matched with locations of keratotic plugs. Type VI: pattern showing a partial, drastic decline in fluorescence intensity occurring on inflamed skin after sunburn. Conclusions: By analyzing the image generated from a highly sensitive television camera equipped with special filters, we could measure turnover rate of the stratum corneum at any small area. The variations in Types IV and V were believed to be derived from keratotic plugs and closed comedo. Except for Type VI, observed on significant skin inflammation, Type II and Type III were believed to be the patterns that reflected variations in turnover rate in stratum corneum itself.     

Recovery functions of common peroneal, posterior tibial and sural nerve somatosensory evoked potentials.

We studied recovery functions of the somatosensory evoked potentials (SEPs) of common peroneal (CPN), posterior tibial (PTN) and sural nerves (SN) using a paired conditioning-test paradigm. The interstimulus interval (ISI) of paired stimuli ranged from 2 to 400 msec. In all SEPs with ISIs of 12-20 msec, the amplitude recovery was close to or beyond 100% of the control response, though their latencies and wave forms were not the same as the control. Further increases of the ISI resulted in significant depression of SEP (late phase suppression), most markedly in CPN, and less prominently in SN-SEP. With a longer than 50 msec ISI there was progressive recovery of SEP, but full recovery differed depending on the nerve stimulated; 400 msec ISI was required for CPN-, 250 msec for PTN- and 100 msec for SN-SEP. The peroneal nerve block by local anesthetic injected just distal to the stimulus electrodes abolished the late phase SEP suppression observed before the nerve block. These findings suggest that the late phase SEP suppression is attributable to the "secondary" afferents as a result of activation of peripheral receptors (muscle, joint and/or cutaneous) by the efferent volley initiated from the stimulus point. The greater and longer duration of peripheral receptor activation in CPN than in PTN or SN stimulation could explain the more pronounced and the longer duration of late phase suppression in CPN-SEP.     

Apoptosis in dendritic cell biology

Apoptosis or programmed cell death regulates many aspects in immunological homeostasis and, thus, controls the initiation, magnitude, duration, and termination of immune responses. Recent studies on dendritic cells (DC), including Langerhans cells (LC), have reinforced this concept by documenting that these antigen presenting cells express surface receptors and ligands that are known to mediate apoptotic cell death and that they are highly susceptible to apoptotic signals. In this review article, four major topics concerning apoptosis in the biology of DC will be overviewed: (a) molecular mechanisms of apoptosis; (b) DC apoptosis induced by various stimuli; (c) regulation of DC apoptosis; and (d) cross-priming and cross-tolerance induced by DC ingesting apoptotic bodies.     

Effect of activated lymphocytes on the regulation of hematopoiesis: enhancement and suppression of in vitro BFU-E growth by T cells stimulated by autologous non-T cells

Autologous mixed lymphocyte culture (AMLR) is an immunologic response with memory and specificity and plays a role in immune regulation. Effects of T cells activated by AMLR were studied in the regulation of in vitro erythropoiesis. AMLR-activated T cells were cocultured with autologous non-T, nonphagocytic peripheral blood mononuclear cells for assaying erythroid progenitor cells (BFU-E). T cells activated for 3 days in AMLR showed significant enhancement of in vitro colony growth by BFU-E. In contrast, activated T cells from day 7 AMLR caused significant suppression of BFU-E growth. Both enhancing and suppressing activities of AMLR-activated T cells were mediated by an la-positive and radiosensitive population within the OKT4+ subset. These observations suggest that AMLR-activated T cells may play a role in the immune-mediated regulation of in vitro erythropoiesis. It is also suggested that heterogeneous T-cell subsets may exert regulatory functions in the regulation of in vitro hematopoiesis.     

Hair follicles serve as local reservoirs of skin mast cell precursors

Several leukocyte populations normally reside in mouse skin, including Langerhans cells and gammadelta T cells in the epidermis and macrophage and mast cells in the dermis. Interestingly, these skin resident leukocytes are frequently identified within or around hair follicles (HFs), which are known to contain stem cell populations that can generate the epidermal architecture or give rise to the melanocyte lineage. Thus, we reasoned that HFs might serve as a local reservoir of the resident leukocyte populations in the skin. When vibrissal follicles of adult mice were cultured in the presence of stem cell factor (SCF), interleukin 3 (IL-3), IL-7, granulocyte-macrophage colony-stimulating factor, and Flt3 ligand, CD45+/lineage-/c-kit+/FcepsilonRI+ cells became detectable on the outgrowing fibroblasts in 10 days and expanded progressively thereafter. These HF-derived leukocytes showed characteristic features of connective tissue-type mast cells, including proliferative responsiveness to SCF, metachromatic granules, mRNA expression for mast cell proteases-1, -4, -5, and -6, and histamine release on ligation of surface IgE or stimulation with substance P or compound 48/80. These results, together with our findings that HFs contain c-kit+ cells and produce SCF mRNA and protein, suggest that HFs provide a unique microenvironment for local development of mast cells.     

Hematopoietic progenitor cells from allogeneic bone marrow transplant donors circulate in the very early post-transplant period

Despite the therapeutic efficacy of allogeneic bone marrow transplantation (allo-BMT), circulating hematopoietic progenitor cells after bone marrow transplantation have not been well characterized. In the present study, we focused on these 'post-transplant circulating progenitor cells (PTCPC)' which may be on their way to bone marrow. We analyzed the number of myeloid progenitor cells (CFU-GM) per 10 ml of peripheral blood (PB) on days 0 (just before transplantation), 1 (8-15 h after the completion of transplantation), 2, 3, 5, 7, 10, 14, 17, 21, 28 and 35 after allo-BMT in five transplant patients using a standard methylcellulose assay. In addition, high proliferative potential colony-forming cells (HPP-CFC) of the harvested donor bone marrow (BM) and day 1 PB of recipients were assayed in five patients. The origin of HPP-CFC from day 1 PB was analyzed by polymerase chain reaction of a DNA region containing a variable number of tandem repeats. The replating potential of these HPP-CFC was evaluated by a secondary colony assay. The proportion of CD38negative cells among CD34+ cells in the harvested BM and day 1 PB was evaluated by two-color flow cytometric analysis. The number of CFU-GM on day 1 ranged from 6 to 73/10 ml PB, and became undetectable on day 5. The reappearance of PTCPC was observed on day 14, along with hematopoietic recovery. The proportion of HPP-CFC among myeloid colonies from day 1 PB was significantly higher than that from harvested BM (44.3+/-10.4% vs 11.3+/-2.1%, respectively, n=5, P=0.0030). These HPP-CFC from day 1 PB were confirmed to be of donor origin. More than 90% of these HPP-CFC had replating potential. Two-color flow cytometric analysis revealed that the proportion of CD34+CD38negative cells was significantly higher in day 1 PB than in the harvested BM (61.0+/-16.5% vs 9.3+/-3.5%, respectively, n=7, P=0.0002). These observations suggest that both primitive and committed transplanted myeloid progenitor cells may circulate in the very early period following allo-BMT.