Tamotsu Tsurumachi

Cytokine regulation on the synthesis of nitric oxide in vivo by chronically infected human polymorphonuclear leucocytes

To determine if nitric oxide (NO) is produced by chronically infected human polymorphonuclear leucocytes (PMNs) in vivo, inflamed exudates (periapical exudates: PE) collected from periapical periodontitis patients were examined. Cell‐free supernatants and cells were separated by centrifugation. Significant levels of nitrite concentrations were observed in the supernatants. The production of inducible NO synthase (iNOS) in highly purified PMNs derived from PEs was then immunocytochemically determined using rabbit anti‐human iNOS antiserum. In vitro, human peripheral blood PMNs (PB‐PMNs) isolated from patients were cultured with a combination of Esherichia coli–lipopolysaccharide (LPS), recombinant human interferon‐γ (rhIFN‐γ) and/or interleukin‐1β (rhIL‐1β). The stimulated PB‐PMNs showed steady‐state levels of nitrite. The stimulation of LPS, rhIFN‐γ and rhIL‐1β showed more NO induction than that of LPS with either IFN‐γ or IL‐1β, suggesting the synergistic effects of cytokines. Cryostat sections of surgically removed periapical tissues were also immunohistochemically examined for iNOS, IFN‐γ and IL‐1β. Two‐colour immunohistochemistry revealed the interaction of iNOS‐producing PMNs and IFN‐γ‐ or IL‐1β‐producing mononuclear cells. On the basis of these data, we concluded that with the stimulation of inflammatory cytokines derived from mononuclear cells, PMNs can spontaneously produce NO at the site of chronic infection. The present studies are consistent with a hypothesis suggesting that PMNs could be regulated and delicately balanced to produce NO by mononuclear cell‐derived cytokines in vivo. NO‐producing cells may play a pivotal role in chronic inflammation.

Expression of inflammatory cytokine genes in vivo by human alveolar bone-derived polymorphonuclear leukocytes isolated from chronically inflamed sites of bone resorption.

Alveolar bone-derived polymorphonuclear leukocytes (PMNs) were characterized for their ability to produce inflammatory cytokines such as interleukin-1α (IL-1α), IL-1β, tumor necrosis factor α(TNFα), and IL-6in vivo. Periapical exudates (PE) were collected from periapical lesions with chronic periapical periodontitis through root canals. Cells and noncellular supernatants were then isolated by centrifugation. The concentration of cytokines present in the noncellular supernatants were determined by ELISA. High concentrations of IL-1α, IL-1β, and IL-6 were detected in PE, however, TNFα was not. PE contains predominantly PMNs (>95% of residing cells) with a few percent of lymphocytes and/or macrophages. These alveolar bone-derived PMNs were purified by the Ficoll-Hypaque gradient method and were analyzed for cytokine mRNA expression using the cytokine-specific reverse-transcription polymerase chain reaction. Highly purified PMNs (>99.5%) isolated from PE expressed significant levels of mRNA for IL-α, IL-1β, and TNFα. IL-6 mRNA was not detected, although a high concentration of IL-6 was detected in supernatants of PE by ELISA. The IL-6 secretion in PE could be derived from macrophages, T lymphocytes, osteoblasts, or fibroblasts around periapical lesions. These data strongly suggest that human PMNs derived from alveolar bone can spontaneously produce IL-1α, IL-1β, and TNFα at sites of inflammation, and probably initiate inflammation and regulate augmentation of bone resorptionin vivo.

The polymeric immunoglobulin receptor (secretory component) in a human intestinal epithelial cell line is up‐regulated by interleukin‐1

Secretory component (SC or polymeric immunoglobulin receptor) on mucosal epithelial cells mediates transcytosis of polymeric immunoglobulin into external fluids and functions as a receptor for polymeric immunoglobulin. SC expression in a human colonic adenocarcinoma cell line, HT‐29 has been reported to be up‐regulated by various cytokines, such as interferon‐&ggr;, tumour necrosis factor‐&agr; and interleukin‐4 (IL‐4). However, up‐regulation of SC by IL‐1 is controversial. In this study, we investigated the effect of human recombinant IL‐1 alone on SC expression in HT‐29 cells in detail. Immunocytochemistry and Northern blot analysis revealed that IL‐1&bgr; increased both the number of SC‐positive cells and SC mRNA expression. Enzyme‐linked immunosorbent assay revealed that IL‐1&bgr; enhanced secretion by HT‐29 cells in both time‐ and dose‐dependent manners. IL‐1&agr; had the same effects on HT‐29 cells. Northern blot analysis demonstrated that cycloheximide and actinomycin D abolished the effect of IL‐1. Moreover, we detected IL‐1 receptor (IL‐1R) type I mRNA in HT‐29 cells by polymerase chain reaction (PCR) and sequenced the PCR‐amplified product. We think that it reflects the possibility of the presence of IL‐1R in HT‐29 cells. From these data, we concluded that IL‐1&bgr; and IL‐1&agr; play regulatory roles in SC expression, and their effects depend on de novo protein synthesis and transcription.

Production of Human-Inducible Nitric Oxide Synthase in Radicular Cysts

To examine if nitric oxide (NO) is produced in radicular cysts, NO synthase (NOS) production was analyzed. Periapical tissues were removed from patients at the time of endodontic surgery. Frozen tissue sections were histologically evaluated with hematoxylin-eosin staining. Production of human-inducible NOS (iNOS) in apical cysts was then immunohistochemically examined. Immunoreactive human iNOS was widely distributed in epithelial cells, endothelial cells, fibroblasts, macrophages, or polymorphonuclear leukocytes. Remarkably, iNOS-positive cells were significantly present around blood vessels, and cells residing apart from the blood vessels showed weak or no iNOS production, suggesting that only cells around blood vessels could be stimulated for iNOS synthesis. These data demonstrated the possibility that several, but not all, cells could be stimulated to synthesize iNOS in inflamed tissues. In the presence of iNOS, NO can be produced spontaneously in periapical lesions and may play a crucial role in the regulation of chronic infection.

Autotransplantation of a maxillary first premolar to replace an ankylosed maxillary incisor: 7-year follow-up

AIM To present the combined endodontic, surgical and orthodontic treatment of an autotransplanted maxillary first premolar for the replacement of an ankylosed maxillary incisor. SUMMARY This case report describes the autotransplantation of a maxillary premolar after the extraction of an ankylosed incisor in a 13-year-old boy. To allow better adaptation of the donor tooth, the buccal root of the first premolar was removed using a diamond bur and the denuded root site was filled with acid-etched composite resin. The palatal root canal was dressed with calcium hydroxide for 2 months before filling with gutta-percha. Autotransplantation of a remodelled maxillary first premolar was achieved to substitute for the ankylosed maxillary central incisor. Orthodontic treatment was performed to correct an Angle Class II malocclusion. Seven years after root canal treatment, the autotransplanted tooth and supporting tissues appeared healthy both clinically and radiographically and were functioning well. KEY LEARNING POINTS • Autotransplantation is a viable option for the treatment of a missing tooth or for the replacement of a traumatized tooth when there is a donor tooth available. • Autotransplantation of a premolar for replacement of a missing anterior tooth is sometimes a suitable alternative to conventional prosthetic rehabilitation or implant treatment in young individuals. • Proper combined endodontic and orthodontic treatment of autotransplanted teeth might be possible without periodontal complications.

Use of a crown fragment to establish favorable temporary crown.

This case describes the esthetic management of a fractured tooth at first visit and its subsequent treatments to restore the esthetics and function. Patients expect adequate esthetics immediately after the first appointment. In addition, they require that esthetics is maintained throughout the definitive treatment phase as well. After the use of the fractured crown fragment as a temporary crown, a root canal treatment was undertaken in a conventional manner. The rehabilitation of the fractured tooth was performed with a post-core-supported prosthetic restoration. Examination at 18 months after treatment revealed good esthetics and normal function.

Developmental disturbance of a mandibular central incisor following trauma to the primary predecessor

When a primary tooth sustains a traumatic injury, development of the permanent tooth can be disturbed, leading to various malformations. This case report details the 7-year follow-up of a developmental anomaly of a central mandibular incisor in a 10-year-old Japanese girl with a history of dental trauma that had occurred at age 4. The trauma had resulted in unusual crown dilaceration in the permanent successor, which exhibited a discoloured and abnormal crown morphology. Radiographic examination revealed crown dilaceration of the tooth, which had a curved root canal.

Primary Management of Dental Trauma

Dental trauma has often a great impact on the patient. Most dental trauma requires immediate action to save the injured teeth. The patient should be examined by a dentist as soon as possible after the trauma which means that the time schedule of the office will be disturbed. On the other hand, reaching an accurate diagnosis is crucial to establishing the prognosis for a traumatized tooth and selecting the appropriate treatment. When the patient in the dental clinic, the patient should be asked about the conditions of trauma and what has happened since it occurred. A thorough examination (radiographs and pulp tests) combined with accurate records forms the basis for an appropriate treatment plan. If teeth are fractured and the soft tissues show lacerations, emergency treatment is chosen to provide a good prognosis for the tooth as well as an instant esthetic result that is well accepted by the patient. The first-aid treatment should focus on psychological effects, repositioning of the teeth, splinting teeth that are mobile or have a root fracture, and repair of fractured crowns. Splinting is indicated for luxation or avulsion and should be maintained for a short period of 2 weeks. Teeth should be splinted rigidly and for a period of at least 3 months in fractures of the root or alveolar bone. When the dentin or the pulp is involved in the coronal fracture, the fracture site should be covered as soon as possible to prevent further irritation or infection of the pulp. Checking the occlusion is also important for the safe of the traumatized tooth. Depending on the type of trauma, follow-up visits should be planned for reexamination or for completion of the treatment. The final treatment will depend on a number of factors, such as the prognosis of the traumatized teeth, the age of the patient, the condition of the rest of the dentition, and the financial resources and wishes of the patient. Appropriate guidelines are needed to assist dentists as well as other health care professionals in producing the good care possible in the most efficient manner. It is very important to promote possible awareness and to educate the population at greatest risk for dental trauma.