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Biomedical subjects

I Hedman

Publications and source records attributed to I Hedman.

At least 19 recordsLinked to original sources
PubMed1991

Muscle structure and function before and after surgery for primary hyperparathyroidism.

In 23 unselected cases of primary hyperparathyroidism (pHPT), muscle strength, morphology and enzymatic activities were studied and electromyography (EMG) performed before and 6 months after surgical treatment. Hypercalcemia was mostly mild or moderate. Nine women undergoing surgery for benign thyroid conditions served as controls regarding muscle strength, while muscle morphologic and enzymatic data were compared with findings in healthy persons of similar age. Only three pHPT patients reported muscle weakness preoperatively, and two were subjectively improved after surgery. Muscle strength did not differ significantly before or after operation between patients and controls: After surgery both groups showed increased isokinetic muscle strength at higher angular velocities. Nor did muscle morphology differ between pHPT patients and controls. No conclusive EMG changes were found before or after surgery for pHPT but postoperatively the pHPT patients showed significant increase in glycolytic but not oxidative muscle enzymes, possibly reflecting early effect of pHPT on especially type II fibers, which previously were shown to be most extensively involved in pHPT. Otherwise no measurable negative effects of mild or moderate pHPT were found on muscle strength or function.

Adult↗
PubMed1986

Primary parathyroid hyperplasia of water-clear cell type. Transformation of water-clear cells into chief cells.

An exceptional case of water-clear cell hyperplasia (WCCH) of the parathyroid glands is presented. Parathyroid tissue was excised at three operations during a period of twenty years before the patient eventually became normocalcemic. Microscopic evaluation of the parathyroids from the first operation showed typical WCCH-findings. However, the parathyroid tissue excised at the last operation was composed of chief cells. There were calcifications and even bone formation. A pigment with the staining and electron-microscopic characteristics of lipofuscin was found in abundance. There were also a few oxyphils. This case shows that clear cells, originally derived from chief cells, can transform into chief cells again.

Adult↗
PubMed1985

An assessment of the risk of developing hyperparathyroidism and thyroid disorders subsequent to neck irradiation in middle-aged women.

We investigated the occurrence of thyroid and parathyroid disorders in 100 women (age 66-70 years) irradiated for cervical spondylosis on average 25 years previously and in 100 control women of similar age. Hyperparathyroidism (HPT), proven by operation, was diagnosed in one patient of each group, and three additional cases were diagnosed biochemically among irradiated women. The difference in incidence is not significant. Nor was there any significant difference in incidence of thyroid disorders. No thyroid carcinoma was found in either group. Even if there is a moderate increase of HPT after neck irradiation in middle-aged women the risk is not so great as to warrant organised follow-up.

Aged↗
PubMed1985

On the mode of action of the pentagastrin test in the carcinoid syndrome.

Provocation with pentagastrin (PG) (0.6 micrograms/kg intravenously) causes a release of serotonin (5-hydroxytryptamine (5-HT] in excess of the metabolizing capacity associated with carcinoid symptoms and a moderate fall in systemic arterial blood pressure in patients with midgut carcinoids and hepatic metastases. In this study PG also caused a release of 5-HT into portal circulation of anesthetized cats with stable peripheral levels of 5-HT in whole blood, indicating an effective hepatic metabolization. A similar response was obtained in the same animal when the PG test was repeated after 3 h. PG provocation was also performed in animals before and after adrenalectomy. Adrenalectomy seems to prevent the PG-induced release of 5-HT into portal circulation, indicating involvement of an adrenal mechanism. PG does not induce 5-HT release from cell suspensions of midgut carcinoid tumors, but such release was induced by incubation with adrenoceptor agonists. These findings indicate the presence of adrenoceptors on carcinoid tumor cells. The mode of action of the PG test may therefore be activation of such adrenoceptors by catecholamines, released from the adrenal medulla at the fall of arterial blood pressure at PG provocation.

Adrenalectomy↗
PubMed1985

Life-threatening hypercalcemia in a case of thyrotoxicosis: clinical features and management. A case report.

Hypercalcemia of thyrotoxicosis is sometimes severe and may mask other symptoms of the disease. A case is presented in which hyperparathyroid crisis was initially suspected. Thyrotoxicosis was confirmed on emergency indication by 131I-uptake test and later by hormone assays. Forced diuresis and prednisolone therapy failed to lower the serum calcium level, but a dramatic effect was obtained with calcitonin. After 10 days the patient was normocalcemic on treatment with only antithyroid drugs. At thyroid resection, five months later, four normal parathyroid glands were found.

Adult↗
PubMed1984

Improvement of muscle strength after treatment for hyperparathyroidism.

Severe muscular weakness and increased fatigability are occasionally encountered in patients with hyperparathyroidism (HPT). An unselected series of 15 HPT patients was studied to assess if subjective fitness could be associated with detectable muscular dysfunction at objective measurements comparing muscle strength before and after surgery. Significant increase in isokinetic strength of knee extension and knee flexion at higher angular velocities was found three months after surgery, suggesting effect predominantly on type II (fast twitch) muscle fibres. The results of the study support the clinical impression that HPT surgery may be beneficial to patients with muscular symptoms.

Aged↗
PubMed1984

Associated hyperparathyroidism and nonmedullary thyroid carcinoma: the etiologic role of radiation.

During an 8-year period ending 1981, 372 patients were treated surgically for hyperparathyroidism (HPT) only, 93 for nonmedullary thyroid carcinoma only, and 19 for combined disease (patients traced by follow-up excluded). Seventy-three of these 484 patients (15.1%) had a history of irradiation to the neck region. When calculated for both the HPT and thyroid carcinoma patients there was a significantly increased incidence of associated HPT and thyroid carcinoma among irradiated individuals (P less than 0.001). In irradiated patients with combined disease the increase in serum calcium level was of the same magnitude as in the patient with HPT only, and the distribution according to stage of carcinomas was similar to that in the nonirradiated patients with thyroid carcinoma only. The present findings are in accordance with the hypothesis that radiation can serve as an etiologic factor in the development of associated thyroid carcinoma and HPT.

Calcium↗
PubMed1983

An evaluation of the risk of developing hyperparathyroidism after 131I treatment for thyrotoxicosis.

It is well established that external radiation to the neck area can act as an initiating factor in the development of hyperparathyroidism (HPT). In the present work the incidence of HPT was studied in a series of 125 patients treated with 131I for thyrotoxicosis and in untreated controls matched for age and sex. No increased incidence of HPT was found among the radioiodine treated patients. The time from treatment to follow-up was 21 years on the average. The most probable reason for the lack of an effect on the HPT-incidence is that variable and mostly low doses of radiation with low dose rates are absorbed in the parathyroids after 131I-treatment for thyrotoxicosis.

Adolescent↗
PubMed1982

Autotransplantation of fresh diseased parathyroid tissue in primary and radiation-induced hyperparathyroidism.

Thirty-five patients with primary or radiation-induced hyperparathyroidism underwent autotransplantation with fresh diseased parathyroid tissue. Due to previous neck surgery (34 percent), concomitant thyroid surgery (66 percent), and a high proportion of multiglandular parathyroid disease (43 percent), all patients ran a high risk of becoming hypoparathyroid, At follow-up , a mean of 28 months after operation, 32 patients had normal parathyroid function, 2 had hyper- and 1 had hypoparathyroid function. The amount of tissue used for transplantation was individually chosen by relating the serum calcium level to the total parathyroid mass. In patients with water-clear cell hyperplasia and thus low endocrine activity on a weight basis, large grafts were needed, whereas less than 120 mg was used in most other cases. In two of our three failures we did not follow these tactics. Our results show that autografting fresh diseased parathyroid tissue can minimize the occurrence of postoperative hypoparathyroidism in patients at high risk of this complication. In no case has recurrent or progressive hypercalcemia developed.

Aged↗
PubMed1981

Radiation-induced parathyroid adenomas and thyroid tumors in rats.

Parathyroid morphology was studied in 45 irradiated and 37 control rats. The irradiated rats received a single parathyroid dose of about 6.5 gray. The rats were killed and autopsied 14 months later. The radiation resulted in fibrosis and depression in weight of the parathyroids. In irradiated rats eleven parathyroid adenomas and four thyroid tumors were found. In control rats no tumor occurred in either parathyroid or thyroid glands. All irradiated rats, including those with a parathyroid adenoma, were normocalcemic.

Adenoma↗
PubMed1978

Massive parathyroid hemorrhage in a case of water-clear cell hyperplasia.

A case of water-clear cell hyperplasia of the parathyroid glands is reported. As far as we know this case is unique in respect of the following features. All the parathyroids were located in the superior mediastinum. One abnormal parathyroid gland was removed with the help of a mediastinoscope. The patient survived a massive parathyroid hemorrhage. This case draws attention to the facts that enlarged parathyroid glands can appear as mediastinal tumours and that massive bleeding can occur in abnormal parathyroid glands.

Adenoma↗