Physiological production of singlet molecular oxygen in the myeloperoxidase-H2O2-chloride system.

The putative role of singlet oxygen (1O2) in the respiratory burst of neutrophils has remained elusive due to the lack of reliable means to study its quantitative production. To measure 1O2 directly from biological or chemical reactions in the near infrared region, we have developed a highly sensitive detection system which employs two InGaAs/InP pin photodiodes incorporated with a dual charge integrating amplifier circuit. Using this detection system, we detected light emission derived from a myeloperoxidase (MPO)-mediated reaction in physiological conditions: pH 7.4, 1-30 nM MPO, 10-100 microM H2O2 and 100-130 mM CI in place of Br without the use of deuterium oxide. The MNPO-H2O2-CI(-) system exhibited a single emission peak at 1.27 microm with a spectral distribution identical to that of delta singlet oxygen. Our results suggest physiological production of 1O2 in the MPO-H2O2-CI(-) system at an intravacuolar neutral pH. The MPO-mediated generation of 1O2, which may have an important role in host defense mechanisms, is discussed in connection with previous results.

Primary neurilemoma of the thyroid gland: report of a case.

Neurilemoma, like other non-epithelial tumors, seldom occurs in the thyroid gland. A 57-year-old man was first referred to our hospital with an asymptomatic anterior neck tumor. A solid tumor was detected in the right lobe of the thyroid and an enucleation of the thyroid tumor was performed. The tumor was 35 x 33 x 33 mm in size, and diagnosed as Antoni A type neurilemoma. We were only able to find seven previously reported detailed cases of primary neurilemoma of the thyroid gland. A review of these cases, however, revealed that neurilemoma tends to develop in the right lobe of the thyroid gland. An operation is thus considered necessary and an enucleation of the tumor is appropriate.

Analysis of thyroid carcinoma based on material registered in Japan during 1977-1986 with special reference to predominance of papillary type.

BACKGROUND: As geographic differences have been observed in the characteristics of thyroid carcinoma, an analysis was made on thyroid carcinoma in the iodine rich country of Japan. METHODS: A total of 10,973 patients with histologically confirmed thyroid carcinoma registered in Japan from 1977-1986 were analyzed. Cases detected incidentally at autopsy and cases of nonepithelial tumor were excluded. This series included approximately 27% of all thyroid carcinoma cases in Japan. RESULTS AND CONCLUSIONS: Histologic distribution showed that papillary carcinoma accounted for 78.4% of cases, follicular carcinoma accounted for 17.2%, medullary carcinoma for 1.4%, squamous cell carcinoma for 0.3%, and anaplastic carcinoma for 2.7%. There is a tendency in Japan to diagnose papillary carcinoma as follicular carcinoma and to diagnose malignant lymphoma as anaplastic carcinoma. It was considered that the percentage of papillary carcinoma was higher and the percentage of follicular carcinoma and anaplastic carcinoma was lower than foregoing values. The characteristics of thyroid carcinoma in Japan were described, and the low incidence of nonpapillary carcinoma compared with papillary carcinoma was discussed in relation to iodine excess as an etiologic factor.

[Comparison of 201T1-chloride and 67Ga-citrate in thyroid tumor scintigraphy].

Twenty-five patients with thyroid tumors were examined by 201T1-chloride and 67Ga-citrate scintigraphy heterochronously in our department. All cases showed the cold nodule with 131I or 99mTc-pertechnetate thyroid scintigraphy and each one was given a histological diagnosis after surgery or excisional biopsy. In 15 cases of thyroid carcinoma, 12 (80%) were positive by 201T1-chloride; 4 (26.7%) were positive by 67Ga-citrate. In examining each histological type, 8 of 9 cases of papillary carcinoma (88.9%) were positive by 201T1-chloride. In 1 negative case the tumor was almost completely encysted; however, they were all negative by 67Ga-citrate. In 2 patients with follicular carcinoma, both of them revealed a positive figure by 201T1-chloride, and one of these with oxyphilic cell carcinoma showed a positive figure by 67Ga-citrate. In 1 case of medullary carcinoma there was slight accumulation with 201T1-chloride, but there was no accumulation with 67Ga-citrate. In 3 cases of undifferentiated carcinoma, 2 patients with small carcinoma showed a negative figure by 201T1-chloride. However, they all showed a positive figure using 67Ga-citrate and this medium also disclosed distant metastases of undifferentiated carcinoma. In 10 patients with thyroid adenoma, 3 (30%) showed a positive figure by 201T1-chloride. Histologically, these were all tubular adenoma, but in all cases of thyroid adenoma 67Ga-citrate revealed a negative figure. From the above mentioned results, the following conclusion were reached. Tumors showing a positive figure by 201T1-chloride that elicited negative results using 67Ga-citrate proved to be differentiated carcinoma or low differentiated types of adenoma. Surgery is indicated in these cases. All of the tumors revealing a positive figure by 67Ga-citrate were highly malignant types. If these tumors showed a negative figure when 201T1-chloride was used, undifferentiated carcinoma was suggested. In undifferentiated carcinoma, 67Ga-citrate scintigraphy is a useful procedure in locating distant metastases, in determining the area to be irradiated, and in judging the effect of therapy.

Comparison of Tl-201 chloride and Ga-67 citrate scintigraphy in the diagnosis of thyroid tumor: concise communication.

Twenty-five patients with thyroid tumors were scintigraphed with both Tl-201 chloride and Ga-67 citrate. All cases showed a focal area of decreased activity with I-131 or pertechnetate (Tc-99m), and each had a histological diagnosis after surgery or excisional biopsy. From the data we conclude the following: (1) Tumors giving a positive scan with Tl-201 chloride but negative results using Ga-67 citrate prove to be differentiated carcinoma or poorly differentiated adenoma. (2) All tumors that are positive with Ga-67 are highly malignant types, and if these tumors are negative by Tl-201, undifferentiated carcinoma is suggested. (3) Ga-67 citrate scintigraphy is a useful procedure in locating distant metastases, in determining the area to be irradiated, and in judging the effect of therapy on undifferentiated carcinoma.

An evaluation of several prognostic factors in the surgical treatment for thyrotoxicosis.

A follow-up survey of 447 patients who had undergone a subtotal thyroidectomy was carried out. In this study, 433 patients were observed, and the follow-up period ranged from one year to ten years. The incidence postoperatively of a recurrence and hypothyroidism was 9.6 and 2.3 per cent, respectively. Transient subclinical hypothyroidism was observed in most patients within three to six months after the operation. This state, however, recovered spontaneously to the euthyroid state within one year. Recurrent hyperthyroidism tends to increase with the lapse of years, while permanent hypothyroidism developed during the first or second year after operation. Results of our investigation suggest that the size of the remnant thyroid appears to play the most important role for an expected long term remission, and the optimal weight of the remnant thyroid should be approximately 10 grams. Although the precise mechanism of remission by surgical ablation of the thyroid has not been clarified, surgical treatment is an effective and safe procedure which controls the condition of the patient with thyrotoxicosis.

Diagnostic usefulness of 201Tl-chloride scintigraphy for preoperative localization of parathyroid tumors.

201Tl-chloride scintigraphy was performed in 10 patients with hyperparathyroidism to assess the localization of abnormal parathyroid glands. This approach proved to be useful in 8 of 10 patients. In particular, an intramediastinal ectopic gland was clearly demonstrated in one patient. Several disadvantages were noted, however, 201Tl-chloride scintigraphy could be the first choice for preoperative localization of abnormal parathyroid glands. If a negative image is obtained, further examinations such as arteriography or parathyroid hormone assay be selective venous blood sampling should be done.

Clinicopathological studies on thyroglossal duct remnant.

The clinicopathological findings in 48 cases underwent complete surgical excision of epithelial tissue of the thyoglossal duct remnants were reviewed. Simple incision of the cyst does not seem to have any therapeutic value and would be followed frequently by recurrence. The widely used Sistrunk procedure 2,6 surgical excision of the central portion of the hyoid bone together with fibrous tract extending to the base of tongue, seems to be warranted in some cases so long as complete eradication of the epithelial tissue can be made.

Altered responsiveness to thyrotropin in thyroid slices of Graves' disease preoperatively treated with excess iodide.

In a previous paper, we demonstrated that the acute administration of excess iodide inhibits the adenylate cyclase-cAMP system in mouse thyroid lobes. In the present study, we examined whether presurgical therapy with stable iodide reduces the responsiveness to TSH in thyroid tissues from patients with Graves' disease. Eight patients with Graves' disease were presurgically treated with methimazole and stable iodide and six were given methimazole alone. Normal tissues from five patients with thyroid nodules were also tested. We have found that stimulation by TSH (5 and 50 mU/ml) of cAMP formation in thyroid slices from patients preoperatively treated with methimazole and iodide is significantly less than in slices from patients treated with methimazole alone. Similar observations were also made with other thyroid stimulators, such as prostaglandin E2 and 4-methylhistamine. Furthermore, thyroid slices from patients treated with methimazole alone responded to TSH to the same degree as slices of normal tissues. The data suggest that one of the reasons for the hyporesponsiveness to TSH in thyroids from patients with Graves' disease is preoperative treatment with stable iodide.