[A case of mandibular gingival cancer T4N0M0 which markedly responded to a combined therapy of nedaplatin with 5-fluorouracil].

We recently experienced a case of mandibular gingival cancer T4N0M0 which markedly responded to a combination therapy of nedaplatin (254-S) with 5-fluorouracil (5-FU). The patient was a 68-year-old male who visited our department with the main complaint of ulceration in the left mandibular gingiva. Biopsy revealed a moderately differentiated squamous cell carcinoma which extended to the mandible, mandibular gingiva, buccal mucosa, half tongue and oral floor on the left side of the face. As a neoadjuvant chemotherapy (NAC), 254-S at a dose of 100 mg/m2 was intravenously administered on day 1, while 5-FU at a dose of 700 mg/m2/day was intravenously administered from day 1 to 5 in succession. Hydration (2,000 ml/day) was performed from day 1 to 3. Adverse reactions observed included thrombocytopenia, anorexia, nausea, vomiting, stomatitis and SIADH, but no sign of renal dysfunction was observed. The clinical outcome was evaluated as CR. Surgery was performed later. Pathological examination of the extracted tissues showed tumor cells in the tongue only, indicating an excellent effect of this combination therapy of 254-S and 5-FU.

Evaluation of the rodent micronucleus assay by a 28-day treatment protocol: Summary of the 13th Collaborative Study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Environmental Mutagen Society of Japan (JEMS)-Mammalian Mutagenicity Study Group (MMS).

To examine whether micronucleus tests can be incorporated into general toxicology assays, we performed micronucleus tests applying the treatment protocols typically used in such assays. In this 13th Collaborative Study of the CSGMT, both rats and mice were tested, although rats were used in the majority of the studies. Fifteen mutagens were tested in rats, mainly by oral (p.o.) administration. Micronucleus induction was evaluated 2, 3, and 4 days, and 1, 2, 3, and 28 days after the beginning of the treatment in the peripheral blood, and at 28 days in the bone marrow. Of the 15 chemicals that induced micronuclei in rats in short-term assays, two chemicals (1,2-dimethylhydrazine.2HCl and mitomycin C) were negative in all our experiments, possibly because of insufficient dose levels. The remaining 13 were positive within the estimated dose range of a general toxicology assay, suggesting the possibility of integrating the micronucleus assay into general toxicology assays. Three patterns were observed in micronucleus induction during the period of repeated treatment: (1) gradual increases in micronucleus frequency with sequential doses, (2) a peak at 3-5 days followed by gradual decreases in micronucleus frequency with sequential doses, and (3) a rapid increase in micronucleus frequency followed by a plateau. We evaluated factors that might have been involved in those patterns, such as the spleen function, target organ exposure, extramedullary hematopoiesis, hypothermia, and hypoxia. Another factor we considered was dosage. Because the dosages employed in a general toxicity assay are usually lower than those used in short-term micronucleus assays, this discrepancy was considered the greatest potential problem for integrating the micronucleus assay into general toxicology assays. Our results indicate that the integration of the micronucleus assay into a 28-day toxicological assay is feasible. To serve this purpose, blood samples collected 4 days after the beginning of treatment and blood and bone marrow samples collected at autopsy should be examined. Furthermore, although it is recognized that mice may be suitable for performing independent micronucleus assays, we propose that rats can provide biologically important and relevant information regarding potential chemical mutagens that can be evaluated under conditions used in the conduct of general toxicology studies.

Effect of temperature on the frequency of chromosome aberrations and micronuclei in cultured Chinese hamster cells.

We previously reported that both hyperthermia and hypothermia induced micronuclei in mouse bone marrow cells (Asanami and Shimono, 1997a, 1997b, 1999). To investigate the effects of temperature on chromosome aberration in vitro, we conducted chromosome aberration and micronucleus tests under hyper- and hypothermic conditions using Chinese hamster lung (CHL) cells. In the chromosome aberration test, we observed positive responses at 40 degrees C and 41 degrees C for 24 hr, and at 42 degrees C for 6 hr and over. In the micronucleus test, we observed positive responses at 31 degrees C, 33 degrees C, and 40 degrees C for 24 hr, and at 42 degrees C for 2 hr. The results suggest that in CHL cells, hypothermic conditions can induce micronuclei while hyperthermic conditions can induce both chromosome aberrations and micronuclei.

Effects of chemically- and environmentally-induced hypothermia on micronucleus induction in rats.

We investigated micronucleus induction in rats treated with chlorpromazine and reserpine, drugs that induce hypothermia. We administered chlorpromazine (31.3--250mg/kg) or reserpine (500--2000 mg/kg) intraperitoneally and measured temperature rectally. Chlorpromazine at 62.5-250mg/kg and reserpine at all doses significantly decreased rectal temperature, although the hypothermic response was weaker than previously reported in mice. Only chlorpromazine at 250mg/kg decreased rectal temperature transiently to <33 degrees C for 20h and induced a statistically significant increase in micronucleated polychromatic erythrocyte frequency. When rats treated with reserpine at 500mg/kg were exposed to an environmental temperature of 16 degrees C for 6, 12, or 24h to keep their body temperature under 33 degrees C, only the 24h treatment group significantly induced micronuclei. In addition, relatively large micronuclei (diameter of micronucleus> or = 1/4 diameter of cytoplasm) accounted for 33.0% of the induced micronuclei, suggesting that hypothermia affected the mitotic apparatus. The hypothermic response to chlorpromazine and reserpine was weaker in rats than in mice, and it was correspondingly more difficult to induce micronuclei in rats with those drugs.

Experimental infusion phlebitis: tolerance pH of peripheral vein.

This study aims to determine the pH that peripheral veins can tolerate. Intravenous nutrient solutions with different pHs (from 4.52 to 6.71) were infused into rabbit ear veins, and the veins were examined histopathologically. After 6-hr infusion at 10 mL/kg/hr, a commercial 2.72% amino acid/7.5% glucose solution with electrolytes (AG) caused obvious phlebitic changes, such as loss of venous endothelial cells, inflammatory cell infiltration, and perivascular edema, in all 6 rabbits because of its low pH (4.52) and high titratable acidity (22 mEq/L). The phlebitis was reduced when the solution was neutralized with NaOH to pH 5.93, and was almost eliminated when the pH was neutralized to 6.49. After 8-hr infusion at 15 mL/kg/hr, AG-adjusted pH to 6.30 caused slight phlebitic changes, but AG-adjusted pH to 6.71 scarcely caused any change. Furthermore, 24-hr infusion of the pH 6.49 solution caused no histopathological changes in 3 rabbits. These results suggest that the tolerance pH for the peripheral vein is about 6.5, and that an infusion solution does not cause phlebitis due to acidity if the pH is not lower than the tolerance pH.

The effect of hyperthermia on micronucleus induction by mutagens in mice.

We administered mitomycin C (0.5 mg/kg) intraperitoneally to hyperthermic-treated mice and examined the effect of hyperthermia on micronucleus induction. Hyperthermia enhanced micronucleus induction. The timing of chemical administration relative to the start of hyperthermic treatment (37 degrees C ambient temperature) influenced micronucleus frequency, and the effect was greatest 2 h after the start of hyperthermic treatment. But the hyperthermic treatment did not change the time course of micronucleus induction. In addition, we investigated the effect of hyperthermia on micronucleus induction by chemicals with different modes of action, i.e., alkylating agents (mitomycin C at 0.1-0.5 mg/kg, cyclophosphamide at 1.25-10 mg/kg), a spindle poison (colchicine at 0.05-1.0 mg/kg), and an antimetabolite (5-fluorouracil at 2.5-50 mg/kg). Hyperthermia enhanced only the clastogenicity of alkylating agents.

Experimental infusion phlebitis: tolerance osmolality of peripheral venous endothelial cells.

This study aimed to determine the osmolality that peripheral venous endothelial cells can tolerate and to clarify the relationship between tolerance osmolality and duration of infusion. Nutrient solutions of 539-917 mOsm/kg, prepared to have no acidic effect, were infused into rabbit ear veins, and the veins were examined histopathologically. In each experiment of 8-, 12-, or 24-h infusion, the higher osmolality solutions caused some phlebitic changes, such as loss of venous endothelial cells, inflammatory cell infiltration, and edema; however, the lowest osmolality solution caused few changes. Infusion of 120 mL/kg of 814 mOsm/kg solution caused phlebitis at 5 or 10 mL.kg-1.h-1, however, the same volume of the same solution scarcely caused phlebitis at 15 mL.kg-1.h-1 because of the shortened infusion duration. These results suggest that the tolerance osmolality of peripheral venous endothelial cells with poor blood flow is about 820 mOsm/kg for 8 h, 690 mOsm/kg for 12 h, and 550 mOsm/kg for 24 h, and that the tolerance osmolality falls as the duration of infusion increases. In conclusion, hypertonic solutions should be infused at as high a rate as is clinically acceptable and compatible with nutrient bioavailability because increasing the infusion rate reduces the duration of infusion and phlebitis.

Transient hypothermia induces micronuclei in mice.

We investigated the effect of hypothermia on micronucleus induction in mouse bone marrow cells. To induce hypothermia, we administered chlorpromazine, which was negative in an in vitro chromosome aberration test, at 3.13, 6.25, 12.5, 25, 50, and 100 mg/kg intraperitoneally. Doses of 12.5-100 mg/kg decreased rectal temperature transiently to less than 33 degrees C. The temperature depression following 25-100 mg/kg lasted for 11 h before returning to normal 24 h later except for the 100 mg/kg treatment group. Doses of 25-100 mg/kg produced a statistically significant (p < 0.01) increase in micronucleated polychromatic erythrocyte frequencies 48 h after dosing. When mice that were administered chlorpromazine at 25, 50, and 100 mg/kg were exposed to an environmental temperature of 30 degrees C for 46 h to keep their body temperature within normal range, the frequency of micronucleated erythrocytes did not increase. In addition, relatively large micronuclei (diameter of micronucleus > or = 1/4 diameter of cytoplasm) accounted for 53-58% of the induced micronuclei. The results suggest that the transient hypothermia of less than 33 degrees C for 11 h induced micronuclei in bone marrow cells, and one possible mechanism was disturbance of the mitotic apparatus.

Dilution is effective in reducing infusion phlebitis in peripheral parenteral nutrition: an experimental study in rabbits.

To clarify conflicting clinical results that had been reported as to whether dilution is effective or not in reducing infusion phlebitis, this study was undertaken. We undertook two experiments with the different infusion conditions in rabbits to confirm the generality and the reproducibility of the results. To test the effect of dilution, 120 mL/kg of solution A (784 mOsm/kg) was infused into rabbit ear veins at 10 mL.kg-1.h-1 for 12 h, and 144 mL/kg of 1.2-fold-diluted solution A (648 mOsm/kg) was infused at 12 mL.kg-1.h-1 for 12 h. Similarly, 120 mL/kg of solution B (718 mOsm/kg) was infused at 5 mL.kg-1.h-1 for 24 h, and 168 mL/kg of 1.4-fold-diluted solution B (514 mOsm/kg) was infused at 7 mL.kg-1.h-1 for 24 h. The infused veins were sampled 24 h after the end of the infusion and examined histopathologically. After the 12-h infusion, phlebitic changes were observed in six of eight rabbits given solution A but in only one of eight rabbits given diluted solution A, although the same quantities of the same nutrients were infused. Also, after the 24-h infusion, phlebitic changes were observed in six of eight rabbits given solution B but in no animals given diluted solution B. The same result that dilution reduced or eliminated phlebitic changes was confirmed in the different conditions. These results suggest that osmolality of the infusion solution is an important factor in the development of phlebitis regardless of infusion volume or infusion rate and that dilution is effective in reducing the phlebitic potential of infusion solutions.

Effects of pH and osmolality on phlebitic potential of infusion solutions for peripheral parenteral nutrition.

In this study, we investigated the phlebitic potentials of several infusion solutions for peripheral parenteral nutrition to clarify the effects of pH and osmolality on the development of infusion phlebitis. A 10% glucose solution with electrolytes (GE, pH 4.93, 727 mOsm/kg), a 10% amino acid solution (AA, pH 6.95, 929 mOsm/kg), or a 5:2 admixture of GE and AA (GEAA, pH 6.46, 779 mOsm/kg) was infused into the rabbit ear vein for 6 hr at 10 mL/kg/hr, and the infused veins were examined histopathologically. Both GE and AA caused phlebitic changes, such as loss of venous endothelial cells, inflammatory cell infiltration, and perivascular edema. However, their admixture, GEAA, caused scant phlebitic changes. These results were as follows: 1) rabbit peripheral veins could tolerate the pH (6.46) and the osmolality (779 mOsm/kg) of GEAA under the conditions of this study; 2) GE caused phlebitis due to its acidity (pH 4.93); 3) AA caused phlebitis due to its hyperosmolality (929 mOsm/kg); and 4) mixing GE and AA eliminated the factors causing phlebitis in each solution. The admixture of GE and another 10% amino acid solution (AB, pH 6.04) at the ratio of 5:2 (GEAB, pH 5.76, 758 mOsm/kg) caused phlebitic changes. Since its osmolality was lower than that of GEAA, it was considered that GEAB caused phlebitic changes due to its acidity (pH 5.76), which was attributed to the acidic amino acid solution used as a component.

Hypothermia induces micronuclei in mouse bone marrow cells.

We investigated the effect of hypothermia on micronucleus induction in mouse bone marrow cells. Reserpine, which was negative in an in vitro chromosome aberration test, was administered intraperitoneally at 1, 5, 10, 100, and 1000 mg/kg to mice to induce hypothermia. Doses of 10-1000 mg/kg decreased rectal temperature to less than 33.3 degrees C from 24 h to 96 h after dosing and produced a statistically significant (p < 0.01) increase in micronucleated polychromatic erythrocyte frequencies (4.0-12.0/1000). When mice that were administered reserpine at 50, 100, or 200 mg/kg were exposed to an environmental temperature of 30 degrees C for 40 h to keep their body temperature within normal range, the frequency of micronucleated erythrocytes did not increase, while it did without increased environmental temperature. In addition, relatively large micronuclei (diameter of micronucleus > or = 1/4 diameter of cytoplasm) accounted for approximately 50% of the induced micronuclei. The results suggest that the low body temperature of less than 33 degrees C for 40 h induced micronuclei in bone marrow cells, and one possible mechanism was disturbance of the mitotic apparatus.

High body temperature induces micronuclei in mouse bone marrow.

The mouse micronucleus test was conducted to investigate the effect of high body temperature on micronucleus induction. Group of 10 male ddY mice were exposed to 30 degrees C for 1, 3 or 6 h, 37 degrees C for 0.5, 1, 2, 3 or 4 h, and 40 degrees C for 1 or 2 h. Bone marrow cells were sampled 24 h after heat exposure. Exposure of mice to 37 degrees C for 3 or 4 h and 40 degrees C for 1 or 2 h raised body temperature to approximately 40.5 degrees C and produced statistically significant increases in micronucleated polychromatic erythrocyte frequencies (8.1 +/- 4.5, 6.0 +/- 2.1, 5.3 +/- 3.3, 7.5 +/- 2.9%, respectively; control frequencies, 2.0 +/- 1.1%). In addition, about 25% of the induced micronuclei were relatively large (diameter of micronucleus > or = 1/4 diameter of cytoplasm). These results suggest that body temperatures of 39.5 degrees C or higher for more than 30 min induce micronuclei in bone marrow cells, and one possible mechanism is disturbance of the mitotic apparatus.

Experimental infusion phlebitis: importance of titratable acidity on phlebitic potential of infusion solution.

The titratable acidity of infusion solutions has never been taken into account in infusion phlebitis. This study aims to clarify the importance of titratable acidity on the phlebitic potential of infusion solutions. Solutions with different titratable acidity (from 0.16 to 12 mEq/L) were infused into the ear veins of 6 rabbits for 6 h at 10 mL/kg/h, and the veins were later examined histopathologically. Even at pH 4.0, a commercial 10% glucose solution scarcely caused any changes because of its very low titratable acidity (0.16 mEq/L). A 10% glucose solution with its titratable acidity adjusted to 3 mEq/L (pH 4.3) with citrate and NaOH, however, caused phlebitic changes in all 6 rabbits, and adjusting the titratable acidity to 12 mEq/L (pH 4.4) increased the degree of phlebitis. On the other hand, a 10% glucose solution with a pH of 5.4 and a titratable acidity of 6 mEq/L caused slight phlebitic changes in half the rabbits. These results suggest that 1) the titratable acidity of infusion solutions is important to the phlebitic potential when the pH is low, 2) when the pHs are similar, the phlebitic potential of infusion solutions depend on the titratable acidity, and 3) the phlebitic potential of infusion solutions can not be estimated by pH or titratable acidity alone.

The suitability of rat peripheral blood in subchronic studies for the micronucleus assay.

To examine the suitability of using rat peripheral blood from animals used in subchronic toxicity studies for micronucleus analysis, we orally administered phenacetin or 6-mercaptopurine for 14 days to groups of six rats and compared their micronucleus frequencies to the bone marrow micronucleus frequencies of rats similarly treated for only 2 days. In the 14-day test, phenacetin significantly increased the frequency of micronucleated reticulocytes in peripheral blood at 500 mg/kg starting from day 9, and at 750 and 1500 mg/kg starting from day 6; 6-mercaptopurine gave a positive response at 20 mg/kg starting from day 6. Positive responses in the bone marrow assay were obtained at the same dose levels. In the 2-day test, micronucleated polychromatic erythrocyte frequencies increased significantly at 1000 and 2000 mg/kg for phenacetin, and at 50, 100, and 200 mg/kg for 6-mercaptopurine. These results suggest that micronucleus assays using peripheral blood from rats in subchronic animal studies of phenacetin and 6-mercaptopurine are feasible and at least as sensitive for the assessment of micronuclei as an acute bone marrow micronucleus test.

[A study of intra-arterial infusion with carboplatin (CBDCA) for 2 patients with maxillary gingival cancer].

In 2 cases of squamous cell carcinoma of maxillary gingiva, carboplatin (CBDCA) was administered by continuous infusion for 5 days, and the clinical outcome and platinum concentrations in the peripheral blood, urine and tissue were investigated. Clinical effects were PR in one of the 2 cases and CR in the other. Platinum concentrations were as high as 3.17 and 13.90 micrograms/g in the tissue, but low in peripheral blood, not exceeding 0.61 and 0.62 micrograms/ml, respectively. These findings suggested that the present method secures the transport of the agent to a local site, with possible reduction of side effects.

Clinical applications and basic studies of laser in dentistry and oral surgery.

In our clinical use of lasers, mainly CO2 laser for oral surgery, we found that the laser had many advantages over an electrome and the laser improved the local control rate for malignant tumors. Low-power laser has been used to treat hypersensitive dentin, to relieve pain caused by neurotic disease around mouth, and to promote the healing of those diseases. The results obtained from the clinical applications showed that irradiation of the hypersensitive dentin with low-power laser was significantly effective in desensitization. An in vitro study showed no effects of diode or He-Ne laser irradiation on the growth of cells, but showed changes in the initial cell adhesion rate. He-Ne laser irradiation to the wound in the skin of hamsters caused to change the activities of the types I and III collagenase. This fact suggest that laser irradiation acted to promote the healing of wound.

Sweet potato beta-amylase. Primary structure and identification of the active-site glutamyl residue.

The complete amino acid sequence of a subunit of sweet potato beta-amylase, a homotetramer, was established by sequence analysis of peptides obtained by digestions with Achromobacter protease I and Staphylococcus aureus V8 protease and by cyanogen bromide cleavage of the S-carboxymethylated subunit. The subunit of the enzyme is a single polypeptide consisting of 498 amino acid residues. It showed 50-60% identity in the amino acid sequence with those of beta-amylases from soybean and barley, while it about 25% with those of three bacterial beta-amylases deduced from the cDNA sequences. Sweet potato beta-amylase was completely inactivated with 2,3-epoxypropyl alpha-D-[U-14C]glucopyranoside. Sequence analysis of the inactivated enzyme revealed that Glu187 was specifically esterified by the affinity labeling with the above reagent, proposing that Glu187 is a potent candidate involved directly in the catalysis with this plant beta-amylase.

Induction of micronucleated reticulocytes by potassium bromate and potassium chromate in CD-1 male mice.

Micronucleus tests of potassium bromate (KBrO3) and potassium chromate (K2CrO4) were conducted with peripheral blood reticulocytes (PB-RETs) of CD-1 male mice dose intraperitoneally. Peripheral blood cells collected from the tail were stained supravitally with acridine orange (AO) using AO-coated glass slides. Both KBrO3 and K2CrO4 induced micronuclei in PB-RETs in the same manner as in polychromatic erythrocytes of bone marrow.

Adenocarcinoma of the sublingual gland.

Primary adenocarcinoma arising in the sublingual gland is very rare. In this report, we have described the details of a case of adenocarcinoma of the sublingual gland. A 27-year-old Japanese male was referred to our department with a swelling of the floor of the mouth on the right side. The patient underwent a wide resection of the lesion and dissection of the right upper neck. Twelve months after his primary surgery, he was readmitted to hospital because of a metastasis in the lower lobe of the right lung and a right lower lobectomy was performed. He has undergone periodical controls for 3 years. No sign of recurrence or metastasis has been observed.

Large exostosis of the mandibular coronoid process. Report of a case.

The clinical experience of a patient with a large exostosis who had a chief complaint of difficulty in opening the mouth is reported. Radiographic examinations, especially tomography and a CT scan, were useful in the diagnosis. Surgical removal is the treatment of choice. The lesion is usually approached by a combination of intraoral and buccal routes; we also employed such an approach in this particular case.