The effect of thyroparathyroidectomy: development of disuse osteoporosis in adult rats

The present investigation was undertaken in order to study the role played by the thyroid and the parathyroid glands in the development of osteoporosis induced by immobilization. One hundred and fifty-three male adult Sprague-Dawley rats were divided into 2 groups. The animals of one group were thyroparathyroidectomized; those of the other group were left intact. Each group was then divided into two subgroups in one of which the right hind leg of the animals were immobilized by elastic adhesive bandages. The animals were observed for varying periods of time up to 16 weeks. Bone mass and composition was determined and the results indicated that disuse osteoporosis occurs in rats in the virtual absence of the thyroid and parathyroid glands. The bone loss of the immobilized femur and tibia is however less pronounced in thyroparathyroidectomized than in intact rats.     

Ultrasonography of the thyroid and parathyroid glands

High-resolution thyroid and parathyroid ultrasonography can play an integral part in the diagnosis and management of patients with clinically undifferentiated cervical masses, thyroid carcinomas or adenomas, and primary parathyroid hyperplasia or neoplasia. Because the study is inexpensive, noninvasive, and easily performed, ultrasonography can be performed as a screening test early in the evaluation of a patient, and ultrasound findings can corroborate the results of other diagnostic procedures, leading to a more accurate diagnosis.     

The role of ultrasonography in the diagnosis of enlarged parathyroid glands

The ultrasonographic diagnosis of parathyroid glands was introduced by the Japanese in 1975. Only after more perfect machines have been introduced, first of all by advancement of "real-time" technique, this method started being used as a routine. The paper shows results of ultrasonographic investigation in 200 patients separated into two groups. In the first group 100 patients were examined with a clinical suspect of primary hyperparathyroidism from which in 30 the existence of parathyroid gland adenoma was diagnosed. Scintigraphy of parathyroid glands was performed in the smaller group of patients; the comparison of these two methods was done, and in 77.7% cases coincidence was found. In the group of 10 operated patients comparison of the two mentioned methods was carried out, with surgical or pathohistologic findings and the coincidence was complete. In the second group 100 patients were examined belonging to the chronical program of hemodialysis, from which in 24 cases existence of swollen parathyroid glands was found. Comparison of ultrasonographic and scintigraphic findings was also done and the coincidence was 68.75%. At the end, the importance of ultrasonography in the first diagnostic stage of swollen parathyroid glands was pointed out.     

Localization of abnormal parathyroid glands of the mediastinum with MR imaging

PURPOSE: To determine the sensitivity of magnetic resonance (MR) imaging for preoperative localization of abnormal parathyroid glands in the mediastinum and to compare the sensitivity of MR imaging with those of scintigraphy and ultrasonography (US). MATERIALS AND METHODS: The prospective sensitivity of MR imaging was compared with those of thallium-technetium scintigraphy and US in 25 patients in whom the abnormal gland was located in the mediastinum at surgery. RESULTS: MR imaging had a much higher sensitivity (22 of 25 cases [88%]) than did scintigraphy (11 of 19 cases [58%]) or US (three of 24 cases [12%]). The most common locations for the mediastinal gland were intrathymic (eight of 25 cases) and paraesophageal (six of 25 cases) sites. CONCLUSION: MR imaging should be considered the modality of choice for preoperative localization in this group of patients.     

Distribution of the solitary adenoma over the parathyroid glands

One hundred and ten patients with primary hyperparathyroidism were studied, in which a normal parathyroid gland was found on the same side as an adenoma (both confirmed by histological examination), and the upper or lower location could clearly be defined during surgery. The distribution of the adenomas over the upper and lower glands was unequal: 61.8 per cent in the superior versus 38.2 per cent in the inferior position. Statistical analysis revealed that this is not a random distribution (p = 0.013). The explanation of this relative predilection is unknown. The finding should not influence the surgical procedure for primary hyperparathyroidism.     

Secretion of parathyroid hormone by abnormal human parathyroid glands in vitro

Radiation survival curves for Lewis lung tumours in the lungs ranging in size from 0-5 to 20 mm3 have been obtained, and a size-dependent variation in hypoxic fraction was found. Cell-survival studies following treatment of various sizes of s.c. tumours indicated that the effects of 60Co gamma-rays and the chemotherapeutic agents 1,3-bas(2-chloroethyl)-1-nitrosourea (BCNU) and cyclophosphamide are all size-dependent. Large pulmonary nodules which had regressed but had not been cured by cyclophosphamide regrew with a radiosensitivity that was characteristic of previously untreated tumours. The results give additional experimental support to the clinical interest in early adjuvant therapy of micrometastases, and sequential combined modality therapy for larger tumours.     

The effect of experimental hypothyrosis on the fine structure of the epiphyseal cartilage of young rats

Authors studied the effect of hypothyrosis induced by thyro-parathyroidectomy and mercaptoimidazole treatment on the fine structure of the proximal epiphyseal cartilage of tibia in growing male rats. It has been established that the cell density of the epiphyseal cartilage decreases in the experimental hypothyrosis, about 30 to 50% of the chondrocytes display degenerative signs, whereas the Golgisystem seems to be well developed. The most characteristic alteration appear in the zones of proliferation and maturation of the epiphyseal cartilage. The endoplasmic reticulum (ER) and mitochondria show a considerable regression also in the chondrocytes displaying minimal or even no signs of degeneration. Elements indicating calcification were encountered more frequently in the cartilaginous matrix of the zones of maturation and calcification under the effect of mercaptoimidazole treatment as compared to the controls, whereas the matrix of the animals operated was poorer in minerals than the corresponding zones of the controls. This difference is attributed by the authors to the different levels of thyrocalcitonin in the two kinds of experiments.     

Cortisol stimulation of parathyroid hormone secretion by rat parathyroid glands in organ culture

Addition of cortisol (10(-6) to 10(-8) M) and related glucocorticoid congeners to cultures of rat parathyroid glands stimulated dose-related increases in parathyroid hormone secretion; the addition of deoxycorticosterone or cortexolone was without effect. Cortexolone, however, inhibited the stimulatory activity of cortisol when both were added to the culture medium. This direct stimulatory effect of cortisol on parathyroid gland secretion may account in part for the increased concentration of parathyroid hormone in the serum of cortisol-treated animals.     

Anatomy of the parathyroid glands of the zebu (Bos indius)

Vasoprotective drugs decrease the vulnerability of blood vessels to cardiovascular risk factors such as hypertension and hypercholesterolemia. Mechanistic treatment end-points of hypertension (normalization of endovascular pressure) may not correct nonhypertensive components of the pathobiology of hypertension. Estrogen replacement therapy, antihypertensive treatment with angiotensin-converting enzyme inhibitors, and manipulations of nitric oxide metabolism may have beneficial effects on vessels in the absence of blood pressure normalization. Estrogens and L-arginine, the precursor of nitric oxide, can partly correct impaired endothelium-dependent vasodilation, a pathophysiologic hallmark of hypertensive states. Angiotensin-converting enzyme inhibitors preserve endothelium-dependent vasodilation and protect arteries against the atherogenic effects of hypercholesterolemia by a non-hypolipidemic, non-hypotensive mechanism.     

Primary diffuse microscopical hyperplasia of the parathyroid glands: surgical importance

In two of 182 patients with verified primary hyperparathyroidism, microscopical hyperplasia was present in all parathyroid glands that were normal in size or only slightly enlarged. All parathyroid glands in another two patients showed microscopical hyperplasia and varied from a normal size of 190 mg. In seven additional patients, microscopical hyperplasia was present in one, several, or all parathyroid glands, which varied in weight from normal to 350 mg. Familial hyperparathyroidism or multiple endocrine neoplasia was evident in five of 11 patients. Contributing to difficulties was the experience in five patients in whom removal of mildly enlarged parathyroid glands corrected hypercalcemia, but definite microscopical abnormalities were not evident by routine histologic study of the glands. Thus, there appears to be a spectrum of abnormalities relative to size and microscopical changes in parathyroid glands of patients with primary hyperparathyroidism. The surgeon should be aware of these patterns of parathyroid hyperplasia that require a search for a fifth parathyroid gland and a subtotal parathyroidectomy.     

Surgical significance of supernumerary parathyroid glands in renal hyperparathyroidism

In secondary hyperparathyroidism (2HPT) fundamentally all parathyroid glands, including supernumerary glands, become hyperplastic, and stimulation of parathyroid glands continues after parathyroidectomy (PTx). Therefore supernumerary glands have special significance during surgery for 2HPT, whether persistent or recurrent HPT. In the present study 570 patients underwent initial total PTx with a forearm autograft. The frequency, type, location, histopathology, and clinical significance of the supernumerary glands were evaluated. At the initial operation 90 supernumerary glands were removed from 82 to 570 patients (14.4%); 12 patients (2.1%) required extirpation of supernumerary glands for persistent/recurrent HPT. Altogether 104 supernumerary glands were identified at operation in 94 of the 570 patients (16.5%). Among these 104 glands, 25 (24.0%) were of the rudimentary, or split, type and 79 (76.0%) of the proper type. Supernumerary glands were most frequently identified in the thymic tongue (53/104, 51.0%); 32 (60.4%) of these 53 glands were identified only microscopically. In 6 of the 570 cases (1.1%), reoperation was required for persistent HPT due to supernumerary glands located in the mediastinum, and 6 patients underwent neck reexploration for recurrence. Histopathologically, 61 of 104 (58.7%) supernumerary glands, including 36 glands recognized only microscopically, showed diffuse hyperplasia, and 43 (41.3%) displayed nodular hyperplasia. Residual small supernumerary glands with diffuse hyperplasia have the potential to be transformed to nodular hyperplasia during long-term hemodialysis. Therefore all parathyroid glands including supernumerary glands should, if possible, be removed at the initial operation. Routine removal of the thymic tongue and careful examination of the regions surrounding the lower poles of the thyroid, especially on the left side, are important steps in the surgical treatment.     

Ultrastructural study of calcium-containing precipitation in human parathyroid glands

Using the potassium pyroantimonate technique for ultrastructural localization of cations and X-ray elemental analysis with both energy dispersive and wave-length dispersive systems, calcium-containing precipitates were found in normal, hyperplastic and adenomatous human parathyroid glands. Differences were observed between oxyphil cells, and suppressed, stimulated and active chief cells in the content and localization of intracellular precipitation. The oxyphil cells and suppressed chief cells possessed precipitates mainly in nuclei and medium-sized and large mitochondria, whereas the stimulated chief cells possessed precipitates in normal-appearing and morphologically altered mitochondria, and in smooth-surfaced vacuoles and cytosol. The active chief cells usually showed a rather sparse precipitation.     

High-strength carbon steels with hereditary fine crystal structure I. The effect of vibrogrinding on the parameters of the fine structure of iron powder particles

Conclusions We investigated the dependence of the specific Surface and of the parameters of the fine structure of powdered pure iron on the duration of vibrogrinding and their change in the process of reduction. It was shown that this is accompanied during the first 15–30 h as a result of deformation polygonization by the formation of a block structure. When ground powders are reduced, processes of polygonization occur intensively; however, regardless of that, the defectiveness of the crystal structure of the metal remains high, and this apparently is bound to have a substantial influence on the processes of dissolving carbon and structurization during the sintering of pellets.Deceased.Translated from Poroshkovaya Metallurgiya, No. 6(282), pp. 46–51, June, 1986.     

The role of parathyroid hormone in the pathogenesis, prevention and treatment of postmenopausal osteoporosis

BACKGROUND: Nuclear deoxyribonucleic acid (DNA) content is a prognostic factor in several tumors, and decisions regarding treatment have been made using this parameter. Nevertheless, there is no agreement in head and neck cancer. The purpose of the present study was to ascertain whether tumor DNA content correlated with prognosis in cases of primary squamous cell carcinoma (SCC) of the oral cavity and tongue base. METHODS: A retrospective study of formalin-fixed, paraffin-embedded tissue from patients with histologically confirmed SCC of the oral cavity and tongue base was performed using flow cytometry. Tumor DNA content was studied in 109 sets of specimens from previously untreated patients. All of them underwent surgical resection at the University "Hospital de La Princesa" between 1982 and 1992. Clinical parameters (age, sex, site of primary tumor, clinical stage, adjuvant therapy received, and disease-free and overall survival) and histologic parameters (histopathologic stage, tumor differentiation, type of inflammatory infiltration, presence of perineural invasion) were recorded in all cases. An exhaustive statistical analysis was applied. RESULTS: Only the histograms of 93 patients were adequate for consideration. In flow cytometric analysis, DNA aneuploidy was observed in 51 tumors (55%). The proportion of aneuploid tumors was significantly higher in advanced-stage carcinomas (p < .05), tumors with perineural invasion (p < .05) and in men (p < .05). In the 24 patients with lymph node metastasis, the incidence of aneuploidy was 82% (19 of 24) (p < .05). The rate of metastasis and aneuploidy increased as the degree of differentiation decreased (p < .05 for both). Patients with aneuploid carcinomas in both early and advanced stages had shorter relapse-free and overall survival periods than did the patients with diploid tumors (p < .001 for both). A Cox regression analysis demonstrated that ploidy was the single most important prognostic factor in determining relapse and death (p < .001 for both). CONCLUSIONS: The results indicate that tumor DNA analysis by flow cytometry appears to be useful as a supplement to clinical and histologic evaluation in predicting the tendency of SCC of the oral cavity and tongue base to metastasize to regional lymph nodes and to predict the outcome of the disease.     

Topographic anatomy and arterial vascularization of the parathyroid glands. Practical application

During the last few years, surgery of primary and secondary hyperparathyroidism has seen remarkable progress. The risks of this surgery are represented essentially by persistant or recurrent hyperparathyroidism and hypoparathyroidism. On the other hand, indications of thyroidectomy are more and more relevant in thyroid pathology. One of the main complications of this surgery is hypoparathyroidism. In these circumstances, the surgeon should know the anatomy and vascularisation of the parathyroids. The purpose of this work is to recall the topographic anatomy and to finalize the origin of the arterial vascularisation in order to improve the results of the thyroid and parathyroid surgery and to diminish its complications.