Location of main occluding areas and masticatory ability in patients with reduced occlusal support.

BACKGROUND: The purpose of this study was to investigate the differences in location of the main occluding area with reduction of occlusal support and to evaluate the subsequent impairment in masticatory ability. METHODS: One hundred and two patients were recruited according to the Eichner's index, which is based on the number of occlusal support zones. Each subject was instructed to clench a piece of temporary stopping in the particular occluding area that was preferably used during mastication. The main occluding area was judged by locating the tooth on which the temporary stopping rested. Subjective masticatory ability was self-assessed by means of a questionnaire. RESULTS: Group classification depending upon the location of the main occluding area was significantly associated with the category of the Eichner's index. The level of masticatory ability was significantly associated with the category of the Eichner's index. Moreover, masticatory ability was significantly more impaired in subjects with main occluding areas at the premolar regions compared to those at the molar regions. CONCLUSIONS: The location of the main occluding area may differ under the influence of the remaining natural teeth. The location of the main occluding area and the masticatory ability are likely to be closely related.

Influence of changing the chewing region on mandibular movement.

BACKGROUND: In the shortened dental arch condition, little is known of how patients adapt their jaw function during mastication to the new oral environment. This study aimed to investigate the changes in mandibular movements when the chewing region was changed from the first molar to the first premolar. METHODS: Thirty clinical residents with natural dentitions were recruited. The subjects were asked to chew a piece of beef jerky using either the first molar or the first premolar on the preferred chewing side. Three-dimensional trajectories of lower incisors and both condyles were analysed using a jaw movement tracking device with six degrees of freedom during the period between the onset and offset of electromyographic bursts from the masseter and anterior temporal muscles. RESULTS: The closing angle of the lower incisors for first premolar chewing was narrower in comparison with that for first molar chewing (p < 0.05). The lengths of the condylar trajectories and the maximum velocities of the condylar movement for first premolar chewing were smaller and slower, respectively, in comparison with those for first molar chewing (both sides; p < 0.01). CONCLUSIONS: The mandibular movement during mastication might be changed to adapt the premolar chewing because of a loss of posterior occlusal supports.

Relationship between tooth contacts in the retruded contact position and mandibular positioning during retrusion.

We conducted a series of studies with the purpose to investigate the locations of tooth contacts in the retruded contact position (RCP) and to discuss their significance in the stomatognathic system. In the present study, the relationship between the locations of RCP contacts and mandibular positioning during retrusion was examined. Thirty dentists and clinical residents were selected as subjects. One specialist in prosthetic dentistry examined each subject for the location of the RCP contacts. The mandibular positioning during retrusion was measured using a mandibular movement analysis system with six degrees of freedom. Originally programmed software was developed. Five reference points were selected: the central lower incisor (point I), the first molars on both sides (points RM and LM) and the condyles on both sides (points RC and LC). Tooth contact was observed most frequently at the second molar, followed by the first premolar. Points I, RM and LM all moved in an inferior-posterior direction, whereas points RC and LC moved in various directions ranging from superior-posterior to inferior-posterior. When the subjects were divided into two groups according to the most anterior tooth of occlusion in the RCP, the condylar positioning tended to be more superior in the group with molar contact than that with premolar contact. These results suggest that the locations of RCP contacts could be an important factor in jaw guidance during retrusion.

Peripheral blood mononuclear cells stimulate progesterone production by luteal cells derived from pregnant and non-pregnant women: possible involvement of interleukin-4 and interleukin-10 in corpus luteum function and differentiation.

Human luteal cells have been reported to express human leukocyte antigen-DR and lymphocyte functional antigen-3 on the cell surface, suggesting physiological interaction between luteal cells and T-lymphocytes through the menstrual cycle into early pregnancy. To elucidate the role of peripheral lymphocytes on corpus luteum differentiation, the effect of peripheral blood mononuclear cells (PBMC) on steroidogenesis by luteal cells was investigated. The production of Th-2 cytokines such as interleukin (IL)-4 and IL-10 by the co-cultured cells was also examined, and the effects of these cytokines on progesterone production by luteal cells were investigated. Corpora lutea were obtained from eight non-pregnant women in the luteal phase and five women in early pregnancy for luteal cell culture. PBMC were isolated from unrelated women in the follicular phase, secretory phase, and early pregnancy. After coculture with allogenic PBMC for 48 h, progesterone production was significantly enhanced by PBMC from the secretory phase and early pregnancy in the non-pregnant luteal cell culture. In the pregnant luteal cell culture, a significant increase in progesterone production was also observed by the co-culture with PBMC from women in early pregnancy, showing that PBMC have a luteotrophic effect. The stimulatory effects of PBMC were also observed in co-culture conditions which prevented direct cell-to-cell interaction with luteal cells, showing the minor influence of mixed lymphocyte reaction. By co-culture with PBMC, the production of IL-10, but not IL-4, was significantly augmented in luteal cell culture derived from non-pregnant women, whereas the production of both IL-4 and IL-10 was significantly enhanced in the luteal cell culture derived from pregnant women. Moreover, IL-4 and IL-10 promoted progesterone production by cultured luteal cells, especially in the luteal cell culture derived from corpora lutea of early pregnancy. These findings indicate that PBMC stimulate progesterone production by luteal cells and suggest the involvement of PBMC in corpus luteum function and differentiation probably via the Th-2-type lymphocytes.

Tissue platinum after clinical treatment with cisplatin or carboplatin in tumor-bearing patients.

Tissue platinum (Pt) levels were measured in tumor-bearing patients treated with either cisplatin or carboplatin. Cisplatin was given by intra-arterial, intraperitoneal, and intravenous (iv) administrations. After death, vertebrae and intervertebral disks were removed from eight human subjects, and livers and kidneys were removed from the half of them. When cisplatin was administered intraperitoneally, Pt of the liver was higher than that of the kidney, and a high content of Pt was detected in the vertebra by comparing with the other administration methods. At the intra-arterial administration of cisplatin, Pt was mainly accumulated in the kidney. At the iv administration of cisplatin, a high level of Pt was found in the vertebra and intervertebral disk, especially at the highest value at 10.31 micrograms/g in the intervertebral disk of one case, whereas a low level of Pt was detected in the liver. On the contrary, it was found that the iv administration of carboplatin did not result in high accumulations of Pt in the liver, kidney, intervertebral disk, and vertebra. Therefore, Pt is accumulated in different organs, depending on the way cisplatin is administered, but Pt is accumulated least in them by the administration of carboplatin.

Novel animal model of lymph node metastasis by intrauterine inoculation of the actively metastatic subline PL3 separated from rat Walker 256 tumor cells.

To investigate the cellular mechanism of lymph node metastasis by tumor cells through the lymphatic vessels in the uterine corpus, we selected an active metastatic subline (PL3) from rat Walker 256 tumor cells and used it to develop a novel experimental model of lymph node metastasis induced by intrauterine inoculation of the tumor cells. Light- and electron-microscopic examinations revealed that the inoculated PL3 cells could actively infiltrate the endometrium from the uterine cavity and form a primary lesion in the uterine corpus. A few PL3 cells in the myometrium were found in the lumen of the peripheral lymphatic vessels on day 7 after inoculation. The regional lymph nodes around the uterus were then invaded by the migrated PL3 cells, and finally (after 3 weeks), most of the parenchyma of the nodes was replaced by metastasized tumor cells. By flow-cytometric analysis, the metastatic PL3 cells expressed CD44, like Walker 256 cells, but lacked integrin alphaL- and alpha4-chains. However, expression of ICAM-1 was considerably down-regulated in the PL3 cells compared to the parent cells. More aggressive invasion was shown by the PL3 cells compared to the parent cells in the in vitro invasion assay. These findings suggest that this experimental model and the separated PL3 cells are suitable for thorough investigations of the unidentified metastatic process and the related cellular behavior involved in the onset of lymphatic invasion by the primary lesion. Furthermore, our model more closely reproduces the clinical conditions related to lymph node metastasis of malignant carcinomas through the lymphatic vessels than does any previously reported animal model.

[Highly effective preoperative intraarterial infusion chemotherapy with CDDP for progressive uterine corpus cancer with a Sister Mary Joseph's nodule].

A 57-year-old female patient complained of atypical genital bleeding and a noxious emanation from her navel. A histological examination of the uterine body and the navel area confirmed a diagnosis of adenocarcinoma. We diagnosed it as IVb stage of uterine corpus cancer with a Sister Mary Joseph's nodule. We selectively administered intraarterial injection chemotherapy (Cisplatin 120 mg, Pirarubicin 40 mg) in the uterus and navel area (three times, once every three weeks) prior to surgery. The isolated uterus showed that the cancerous tissue had been eradicated, and we judged the cancer to be grade 3 following histopathological effective grading standards. The metastasis exhibited extreme shrinkage, but affirmed changes in the tumor quality. Currently, the patient is receiving maintenance therapy of 600 mg of Hysron H, and 600 mg of UFT. There are no indications of recurrence, and the patient is progressing well.

Accumulation of platinum in the intervertebral discs and vertebrae of ovarian tumor-bearing patients treated with cisplatin.

Platinum was determined by the inductively coupled plasma mass spectrometry (ICP-MS) in the intervertebral discs and vertebrae of ovarian tumor bearing patients treated with cis-diamminedichloro-platinum (II) (cisplatin). Platinum was 0.05 ng/mL at the absolute detection limit, and platinum was undetectable in the intervertebral discs and vertebrae of human specimens without cisplatin treatments. On the other hand, platinum was detected in the intervertebral discs and vertebrae of patients administered cisplatin, and platinum concentration was at levels of 1.06-10.31 micrograms/g dry tissue in the intervertebral discs and 0.60-1.28 micrograms/g dry tissue in the vertebrae, respectively. The platinum level of intervertebral discs was 4.3-fold higher than that of the vertebrae. Thus, platinum accumulates greatly in the intervertebral discs and somewhat in the vertebrae after administering cisplatin to patients for therapy.

[Local injection of high-dose CDDP to the advanced gynecological cancer].

We investigated the efficacy of local injection of high-dose CDDP. The subjects were 16 patients with advanced gynecological cancer or tumor recurrence, in whom systemic administration of CDDP was inadvisable because of advanced age or associated complications (12 cases of cervical carcinoma, 2 cases of endometrial carcinoma, 1 case of ovarian carcinoma, and 1 case of vulvar carcinoma). In 14 cases, CDDP was injected locally to the tumor mass, using a single dose of 50-300 mg. In 2 cases, a single dose of 10-20 mg of CDDP was infused into the uterine cavity. The effects of the therapy were evaluated by cytodiagnosis, tumor markers, CT, and performance status. In all cases, an antitumor effect was noted, and seven subjects survived for at least 24 months following these therapy with CDDP. One patient developed vesicovaginal and rectovaginal fistulae after local injection of CDDP following high-dose radiotherapy. We investigated the plasma concentrations of free and total platinum after CDDP application with doses from 60-200 mg/body. Plasma concentrations showed a biphasic pattern (phase alpha and phase beta), and the peak plasma concentration of CDDP was lower than that following intravenous administration of the same dose. From these results, it was suggested that a large dose of CDDP can be injected into the tumor tissue itself and the surrounding tissue with comparatively few side effects. It will be possible to administer large dose of CDDP in this way to the terminal patients to whom there is currently no other appropriate method of treatment. The performance status of our subjects was improved, and we expect that wider use of this method will improve the quality of life for end-stage patients.

Experimental local administration of CDDP to in vitro models of gynecological malignant tumors transplanted into nude mice (compared with medroxyprogesterone acetate orally administered).

In order to develop a new method of administration for CDDP, in vitro models of malignant tumors in the field of gynecology were prepared using two cell lines maintained by the authors, and fundamental experiments on the topical injection of CDDP were carried out. In experimental topical injection of CDDP in tumor-bearing nude mice, the test drug demonstrated an excellent tumor regression effect and an inhibitory effect on tumor growth. In the histopathologic examinations, specific necrosis of tumor cells was observed. It was confirmed that this is a highly safe method, as tissue separation, ulceration, or hemorrhagic lesions attributable to the local administration of CDDP were not observed. In the present study, treatment with oral medroxyprogesterone acetate was also used. At the doses used in this study, however, no inhibitory effect on tumor growth or synergism between medroxyprogesterone acetate and CDDP was observed. Topical injection is an excellent pharmacodynamic method that permits the injection of free platin into the tumor itself or in the boundary area between the tumor and normal tissues, with no loss of the drug, and it is considered a safe and effective mode of local administration. Intra-arterial injection of this drug alone or in conjunction with OK-432 can also be used, even though further studies will be required to determine the optimum dosage and reduce side effects. At present, data are being collected on terminal cancer patients for whom no other therapy is available. In the near future this method of administration is expected to be utilized in the clinical treatment of malignant tumors, be it early tumor or progressive cancer.