In vivo comet assay of a novel galacto-oligosaccharide in rats

A novel galacto-oligosaccharide (GOS) manufactured by a two-step enzyme reaction of lactose was examined in a comet assay for its potential to induce DNA damage in vivo by estimating the DNA fragmentation level in the cellular nuclei of the glandular stomach, colon, and peripheral blood. GOS was orally administered at doses of 0 (vehicle alone), 500, 1000, and 2000 mg/kg/day to five male Crl: CD(Sprague Dawley) rats per group three times (48, 24, and 3 h before the animals were terminated). The specimens were prepared in accordance with the standard protocol (version 14.2) of the “International Validation of the In Vivo Rodent Alkaline Comet Assay for the Detection of Genotoxic Carcinogens” organized by the Japanese Center for the Validation of Alternative Methods. No significant differences in the percentage of DNA in the tail were observed between the GOS-treated groups and vehicle controls in any of the organs evaluated. Additionally, no GOS-related clinical signs or effects on body weight were seen. Based on these results, the comet assay of GOS in the glandular stomach, colon, and peripheral blood using rats was judged negative. Therefore, it is concluded that GOS did not induce DNA damage in vivo under the conditions employed in this study.

Safety of a novel galacto-oligosaccharide: Genotoxicity and repeated oral dose studies

A series of safety tests were undertaken on a novel galacto-oligosaccharide (GOS) produced from lactose by a two-step enzymatic process involving Sporobolomyces singularis and Kluyveromyces lactis. Bacterial reverse mutation and chromosomal aberration tests, with or without metabolic activation, were performed. These tests showed no mutagenesis in the Ames assay or in Escherichia coli WP2uvrA, and no chromosomal aberrations in cultured fibroblast cells from Chinese hamster lungs (CHL/IU). Micronuclei were not induced in the reticulocytes of mouse peripheral blood following oral administration of GOS. In a 90-day repeated oral dose toxicity study in rats, GOS was administered at 0, 500, 1000 and 2000 mg/kg to male and female Sprague-Dawley rats. There were no GOS-related changes in clinical signs, body weight, water intake, feed intake, urinalysis, ophthalmology, haematology, blood chemistry, organ weights, gross pathology or histopathology in any of the treatment groups compared to the control group. The no observed adverse effect level (NOAEL) of GOS was at least 2000 mg/kg/day in both males and females.

Strategy for genotoxicity testing: Hazard identification and risk assessment in relation to in vitro testing

This report summarizes the proceedings of the September 9-10, 2005 meeting of the Expert Working Group on Hazard Identification and Risk Assessment in Relation to In Vitro Testing, part of an initiative on genetic toxicology. The objective of the Working Group was to develop recommendations for interpretation of results from tests commonly included in regulatory genetic toxicology test batteries, and to propose an appropriate strategy for follow-up testing when positive in vitro results were obtained in these assays. The Group noted the high frequency of positive in vitro findings in the genotoxicity test batteries with agents found not to be carcinogenic and thought not to pose a carcinogenic health hazard to humans. The Group agreed that a set of consensus principles for appropriate interpretation and follow-up testing when initial in vitro tests are positive was needed. Current differences in emphasis and policy among different regulatory agencies were recognized as a basis of this need. Using a consensus process among a balanced group of recognized international authorities from industry, government, and academia, it was agreed that a strategy based on these principles should include guidance on: (1) interpretation of initial results in the "core" test battery; (2) criteria for determining when follow-up testing is needed; (3) criteria for selecting appropriate follow-up tests; (4) definition of when the evidence is sufficient to define the mode of action and the relevance to human exposure; and (5) definition of approaches to evaluate the degree of health risk under conditions of exposure of the species of concern (generally the human). A framework for addressing these issues was discussed, and a general "decision tree" was developed that included criteria for assessing the need for further testing, selecting appropriate follow-up tests, and determining a sufficient weight of evidence to attribute a level of risk and stop testing. The discussion included case studies based on actual test results that illustrated common situations encountered, and consensus opinions were developed based on group analysis of these cases. The Working Group defined circumstances in which the pattern and magnitude of positive results was such that there was very low or no concern (e.g., non-reproducible or marginal responses), and no further testing would be needed. This included a discussion of the importance of the use of historical control data. The criteria for determining when follow-up testing is needed included factors, such as evidence of reproducibility, level of cytotoxicity at which an increased DNA damage or mutation frequency is observed, relationship of results to the historical control range of values, and total weight of evidence across assays. When the initial battery is negative, further testing might be required based on information from the published literature, structure activity considerations, or the potential for significant human metabolites not generated in the test systems. Additional testing might also be needed retrospectively when increase in tumors or evidence of pre-neoplastic change is seen. When follow-up testing is needed, it should be based on knowledge about the mode of action, based on reports in the literature or learned from the nature of the responses observed in the initial tests. The initial findings, and available information about the biochemical and pharmacological nature of the agent, are generally sufficient to conclude that the responses observed are consistent with certain molecular mechanisms and inconsistent with others. Follow-up tests should be sensitive to the types of genetic damage known to be capable of inducing the response observed initially. It was recognized that genotoxic events might arise from processes other than direct reactivity with DNA, that these mechanisms may have a non-linear, or threshold, dose-response relationship, and that in such cases it may be possible to determine an exposure level below which there is negligible concern about an effect due to human exposures. When a test result is clearly positive, consideration of relevance to human health includes whether other assays for the same endpoint support the results observed, whether the mode or mechanism of action is relevant to the human, and - most importantly - whether the effect observed is likely to occur in vivo at concentrations expected as a result of human exposure. Although general principles were agreed upon, time did not permit the development of recommendations for the selection of specific tests beyond those commonly employed in initial test batteries.

Comparison of innervated and noninnervated free flaps in oral reconstruction

Thirteen patients who had undergone ablative surgery for advanced squamous cell carcinoma in which more than half of the tongue had been resected underwent reconstruction in which the cutaneous nerve of a free flap was anastomosed to the stump of the transected lingual nerve. Eight of the patients underwent reconstruction with an innervated anterolateral thigh flap and five patients underwent reconstruction with an innervated rectus abdominis musculocutaneous flap. Sensory recovery of the flap at least 6 months postoperatively was compared in these 13 patients and in 16 additional patients who received noninnervated versions of the same flaps for the same defect. The degree of sensory recovery of innervated thigh flaps was significantly greater than that of noninnervated ones in all modalities and that of innervated rectus abdominis flaps was also greater than that of noninnervated flaps, except for hot and cold perception. These results indicate that sensory regrowth occurs in most areas through the surgically created pathways. However, results of Semmes-Weinstein testing showed that recovery did not reach the level of protective sensation in either type of innervated flap. Although these findings must be followed by additional objective and functional tests and the need for sensory reeducation should be considered, this simple operative procedure can improve postoperative intraoral function and should be attempted whenever possible after ablative surgery.

A new concept and technique for reconstruction of the lower pharyngeal space using the free jejunal graft

OBJECTIVE

To report on a new concept and simple operative procedure to conform the diameter of the oral end of free jejunal grafts to that of pharyngeal defects for reconstruction of the lower pharyngeal space.

DESIGN AND METHODS

A preliminary study showed that the jejunum is supplied by a highly vascular network and that longitudinal paramesenteric incisions can be made without disturbing the blood supply of the jejunum. We then developed the following operative procedure. The position of the highest point of the pharyngeal defect and the site of the recipient vessels are determined. The free jejunal graft is positioned with its mesentery in correspondence with the location of the recipient vessels. The position of a longitudinal incision 180 degrees to the highest point of the defect is then determined. After the oral border of the jejunum is opened with scissors, a pharyngojejunal end-to-end anastomosis is performed.

PATIENTS

Eighteen patients with defects of the lower pharyngeal space after cancer treatment.

RESULTS

We transferred jejunal grafts in 18 patients using this operative procedure. In 7 of these patients, paramesenteric incisions were made. The lengths of the incisions ranged from 2 to 8 cm. Transfer was successful in all 18 patients. Postoperative leakage occurred in 1 patient in whom an antimesenteric incision had been made; however, a fistula did not develop.

CONCLUSIONS

Our method allows defects of the lower pharyngeal space to be reconstructed with end-to-end anastomosis of free jejunal grafts regardless of the location of the defect or of recipient vessels. This method is simple and appropriate for correcting large pharyngeal defects.

Versatility of the free anterolateral thigh flap for reconstruction of head and neck defects

OBJECTIVE

The anterolateral thigh flap has many advantages in head and neck reconstruction. However, it has not yet come into widespread use because of the anatomic variations of its perforators. Herein, we describe a safe operative technique related to the patterns of the perforators and discuss its wide versatility.

SETTING

A national cancer center hospital.

PATIENTS

Thirty-eight anterolateral thigh flaps were transferred. Confirmation and dissection of the flap pedicle were simultaneously performed with tumor resection. The design and elevation of the flap were carried out immediately after the tumor resection was completed.

RESULTS

From the study of the anatomic variations of the perforators, septocutaneous patterns were recognized in 10 cases (26.3%) and musculocutaneous patterns in 28 cases (73.7%). All flaps were easily and safely elevated with our techniques. Thirty-six flaps survived. Partial necrosis was noted owing to excessive thinning procedure in one patient and total necrosis was noted owing to venous thrombosis at the anastomosis part in another patient.

CONCLUSIONS

We found that the anterolateral thigh flap has numerous advantages. It is possible to perform the flap elevation and the tumor resection simultaneously. The flap is generally thin and is suitable for reconstruction of intraoral defects. Combined flaps with neighboring tissues and other, distant flaps can be used. Furthermore, since our technique minimizes the problems of confirmation and dissection of the perforators, we conclude that this flap can be successfully used to repair a variety of large defects of the head and neck.

Radiotherapy of T1 glottic cancer with 6 MeV X rays

We treated 154 patients with T1 glottic carcinoma with 6 MeV X rays through 16 cm2 parallel-opposing open fields on a free set-up delivering a median dose of 67 Gy in 6 2/3 weeks. Observed and relative 5-year survival rates for all patients were 87% and 100%, respectively. The local control rate at 5 years was 89%. Of 18 patients who clinically had local recurrence, 17 were salvaged by a secondary treatment. There were no complications requiring medical or surgical attention. A tendency toward increasing local control rates with increasing total doses was observed in the range between 57.5 Gy and 72.5. No significant correlation was found between local control rates and field size, daily dose, or the technique used. A tendency toward a lower local control rate was noted for patients whose anterior commissures were grossly involved; however, it is not known if this could be attributed to the use of 6 MeV X rays. The results are comparable to those obtained with 60Co as reported in the literature. It is concluded that 6 MeV X rays on a free set-up delivering 65-70 Gy in 6 1/2-7 weeks can be used satisfactorily for the treatment of early glottic carcinoma.

Stage I-II carcinoma of the anterior two-thirds of the tongue treated with different modalities: a retrospective analysis of 244 patients

Treatment results of 244 patients with stage I-II cancer of the mobile tongue were analyzed according to the modalities employed (implantation, surgery, cryosurgery and intraoral irradiation). Overall local control rates at three years were 90 +/- 3% for implant, 89 +/- 7% for cryosurgery, and 84 +/- 9% for surgery. Local control rates in stage II patients treated with intraoral electron irradiation, however, were only 50 +/- 13%. Five-year survival rates were 72 +/- 3% with no significant differences observed in patients with either stage I or stage II regardless of treatment modality. Sixty percent (29/48) of the patients with local recurrences were salvaged by the second treatment. Since the local control and survival achieved by these modalities were similar, with the exception of patients with stage II treated by intraoral electron irradiation, we recommend interstitial implantation with iridium, intraoral electron irradiation or surgery for patients with T1 tumors, and iridium implantation or surgery for patients with T2 tumors. For those with superficial lesions measuring 5 mm or less in thickness, cryosurgery is being offered as an alternative. The patient can choose the treatment modality taking into account his/her age, sex and profession.

Multiple primary cancers in patients with squamous cell carcinoma of the oral cavity

During the 27 years between 1962 and 1988, 984 patients visited the National Cancer Center Hospital for previously untreated squamous cell carcinoma of the oral cavity and lip. The records of all these 984 patients were reviewed to determine the incidence of additional primary carcinoma. 1) One hundred and thirty-five additional carcinomas developed in 111 patients (11.2%) during 5,689.2 person-years of observation. The incidence of additional primary carcinoma was 23.7 per 1,000 person-years. 2) The cumulative rate of additional primary carcinoma during the first five years of observation showed a tendency to increase in the most recently treated patients (from 1980 to 1988). 3) The observed-to-expected ratio (O/E ratio) for all sites was 2.77 and this is significantly high (P less than 0.01). The calculation of the O/E ratio for each site revealed significantly high risks in the oral cavity and pharynx, esophagus and skin. The O/E ratio for the oral cavity and pharynx was extremely high (79.45). 4) The O/E ratio for all sites in each year of follow-up was the highest in the first year, stayed nearly constant from the second to 14th years, and decreased gradually afterwards. Significantly high risk was observed until the 13th year of follow-up. Patients with oral squamous cell carcinoma must be under frequent and regular examination for almost 15 years.

Surgical management of squamous cell carcinoma of the floor of the mouth

A retrospective review is presented of 76 patients, referred to the National Cancer Center Hospital, Tokyo, who underwent surgical management for squamous cell carcinoma of the floor of the mouth during the period March, 1969, to May, 1988. Of the 76 patients, 34 (45%) were treated by surgery alone, 19 (25%) by cryosurgery and 23 (30%) by a combination of surgery and another treatment modality, either irradiation (22 patients) or chemotherapy (one patient). Fifty-three percent of the patients had stage III or IV disease. Twenty-two patients (29%) developed recurrent disease during follow-up. Eighty-five percent of the treatment failures were identified within 24 months of treatment. The most common site of recurrence, seen in 14 out of 22 cases, was the neck. The actuarial five-year survivals for patients were: stage I disease, 96%; stage II, 79%; stage III, 66%; stage IV, 49%. Recent technical advances, allowing extensive resection and reconstruction in the surgical management of this kind of tumor, have improved the prognosis even for patients with advanced disease.

[An evaluation of excisional biopsy for tongue carcinoma]

An evaluation of excisional biopsy for tongue carcinoma (T1, T2) as a surgical treatment was performed. Forty-seven patients who received excisional biopsy among 394 patients with tongue carcinoma (T1, T2) treated in National Cancer Center Hospital during 24 years were examined. These patients were divided into following three groups: group a) patients treated with excisional biopsy only, group b) those treated with excisional biopsy and cryosurgery, group c) those treated with excisional biopsy and radiotherapy. We examined local control rate of these groups, degree of differentiation in histopathological examination, and median cancer free surgical margin. From these we obtained following results: 1) There was no significance in local control rate among these three groups (group a 77%, group b 84%, group c 45%) 2) There were no local recurrences in the patients with cancer free margin of 5 mm or more except when the histopathology showed perineural invasion, lymphatic vessel invasion, and/or deep invasion to the muscle. 3) Even if we had cancer positive surgical margin with excisional biopsy, we could obtain high local control rate (75%) with additional cryosurgery. We conclude that excisional biopsy for tongue carcinoma (T1, T2) is a good method for primary therapy.

[Quality of life in treated head and neck cancer patients]

Sixty-Seven patients with head and neck cancer have been studied with respect to their quality of life after their treatment. The Grogono Woodgate index was used to evaluate their quality of life, the quality of life of patients treated for laryngeal cancer was excellent, even if they underwent total laryngectomy. On the contrary, however, patients who had hypopharyngeal cancer and had undergone a pharyngolaryngoesophagectomy had the lowest indices. As for patients with an oral cancer, their indices were high if the cancer was being controlled by radiotherapy.

Intraarterial infusion of 4'-O-tetrahydropyranyl-adriamycin for head and neck tumors

THP-adriamycin was administered in a dose of 5 to 20 mg, 3 times a week, and the results showed 4 cases of CR, 5 cases of PR, 3 cases of MR and 2 cases of NC with the accumulated total dose of less than 100 mg. Histological effects were slight in a total dose of less than 50 mg, while the effects appeared in a total dose of 60 to 70 mg and further effects were obtained after about 1 week of the termination of the therapy. Leukopenia occurred in 6 of 14 cases. The side effects of THP-adriamycin were milder than those of ADM.

[THP-adriamycin in head and neck tumor]

Primary effects and side-effects of a new anthracycline antineoplastic agent, THP-adriamycin (THP-ADM), were examined in 20 patients with malignant head and neck tumors. According to a classification by tumor sites, there were 6 cases of oropharynx, 6 of nose and sinuses, 3 of tongue, 2 of floor of mouth, 2 of neck and 1 of external auditory meatus. According to the tissue classification, there were 11 cases of squamous cell ca., 6 cases of malignant lymphoma, each one case of anaplastic ca., carcino sarcoma and adeno cystic ca. There were 16 previously untreated cases and 4 pretreated cases. Twelve cases received THP-ADM by intraarterial injection and 8 cases by the same dose. 10 to 20 mg/body 3 times a week, in a total of 40 to 100 mg. 2 CR, 5 PR, 3 MR and 4 NC in 14 cases with carcinoma, and 2 CR, 3 PR and 1 MR in 6 cases with malignant lymphoma were obtained. Among 12 cases receiving intraarterial injection, 3 CR and 5 PR were obtained. The decrease of WBC counts below 3000/mm3 after THP-ADM administration was observed in 9 cases. Side effect of THP-ADM appeared to be less severe than that of Adriamycin.

[Clinical results of FAR (5-FU, vitamin A, and radiation) therapy in head and neck cancer]

Combination therapy of 5-FU, vitamin A and radiation (FAR therapy) was given to 50 patients with squamous cell carcinoma of the head and neck. The primary effect was observed in 22 patients who received FAR therapy as radical therapy. Among them, only 4 patients had recurrence or metastasis, and death was none. FAR therapy was given to 4 patients as pre-operative therapy and to 2 patients as post-operative therapy. However, the number of cases was not enough for us to draw any conclusion. In the group of 22 patients consisting of patients with recurrence or metastasis and patients who refused operation or were unresectable, no primary effect was observed only in 4 patients. Among a total of 50 patients, only 4 patients did not show a primary response to FAR therapy, 19 had relapse, 19 died (6 cases of them died from other causes), and 31 are still alive. There were no patients having severe side effects. From these results, FAR therapy seemed to be worth trying in treatment of head and neck cancer.