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Biomedical subjects

S Ljunghall

Publications and source records attributed to S Ljunghall.

384 records · Page 22Linked to original sources

The role of the pathologist in diagnosis and surgical decision making in hyperparathyroidism.

Hyperparathyroidism has been diagnosed with increasing frequency in recent decades. The concomitant awareness that the disease may be the cause of a concealed morbidity and even an increased mortality has resulted in more liberal indications for surgery. Many patients currently undergo surgery on the grounds of only mild hypercalcemia and in the absence of any apparent clinical symptoms. This policy of early surgical treatment has emphasized the importance of a histopathological parathyroid diagnosis, since many of these patients exhibit chief cell hyperplasia and minimal glandular enlargement. Light microscopic examination of frozen sections stained with hematoxylin-eosin and with stains for demonstration of cytoplasmic fat in the parathyroid chief cells, and appropriate weight estimates of the parathyroid glands, constitute the conventional, intra-operative basis for the diagnosis. The use of specific antiparathyroid antibodies is an important new tool in the histopathological parathyroid examination, mainly because of the ability to demonstrate the cause of increased parathyroid hormone release from the pathological parathyroid tissue. A careful histopathological examination in combination with gross inspection of the parathyroid glands by an experienced eye should contribute to adequate surgical treatment and minimize errors in operative management in patients with hyperparathyroidism.

Adenoma↗

Dynamics of parathyroid hormone release and serum calcium regulation after surgery for primary hyperparathyroidism.

Analysis of 14 patients with primary hyperparathyroidism (HPT) prior to and during the first year after parathyroid surgery disclosed that the operation was associated with rapid reductions of intact serum parathyroid hormone (PTH) and total serum and ionized plasma calcium values. A decreased urinary calcium excretion, a gradual elevation of renal calcium reabsorption, a transient reduction of serum calcitriol, and a late increase in 25-hydroxycholecalciferol values were also noted. Dynamic tests of parathyroid function by EDTA infusion and an oral calcium load revealed a sigmoidal relationship between serum PTH and calcium levels, and that parathyroid surgery induced considerable changes in both the position and slope of the dose-response curve. It was also apparent that PTH release was submaximally stimulated event at periods of hypocalcemia. The findings substantiate that adjustments of PTH release to acute alterations of serum calcium occur along the prevailing dose-response relationship, while stimuli being maintained for longer periods of time induce compensatory shifts in the position and slope of this curve. It is further suggested that unknown factors with PTH-like function may participate in the calcium regulation after surgery for primary HPT.

Adult↗

Technical aspects of magnetic resonance imaging in parathyroid gland lesions.

Two patients with primary hyperparathyroidism were examined before parathyroid surgery with magnetic resonance imaging at 0.35 tesla in order to analyse optimal methods of visualization. Two large parathyroid glands in the neck had long transverse relaxation times which rendered them clearly visible in T2-weighted images as structures of a signal intensity higher than that of the surrounding. Large parathyroid lesions may thus be easily detected by magnetic resonance imaging provided proper examination parameters are employed.

Adult↗

Cytologic diagnosis of a medullary carcinoma of the thyroid by Sevier-Munger silver staining and calcitonin immunocytochemistry.

A medullary carcinoma of the thyroid was preoperatively diagnosed on ultrasonically guided fine needle aspiration biopsies. After cytocentrifugation, the tumor cells displayed a dense cytoplasmic silver granulation with the Sevier-Munger technique when applied to air-dried or acetone-ethanol-fixed samples and an obvious calcitonin immunoreactivity after fixation in Bouin's fluid. These methods may prove useful in the identification of nonpalpable metastases and recurrences of medullary carcinomas of the thyroid, especially since the cytologic typing of medullary thyroid carcinoma cells may be difficult with routine stainings.

Biopsy, Needle↗

Surgical findings and results of subtotal and total parathyroidectomy in hypercalcemic patients with uremic hyperparathyroidism.

Surgical and histopathologic findings and results of subtotal resection and total parathyroidectomy with autotransplantation were evaluated in 82 hypercalcemic patients with uremic hyperparathyroidism. The mean preoperative serum calcium concentration was 2.89 mM, and the highest values were associated with more rapidly progressing hypercalcemia. Despite greatly increased total weight of the parathyroid tissue (mean 1,509 mg), 34 patients had one to five normal-sized parathyroid glands. The incidence of such glands decreased with total gland weight. Nodular hyperplasia was found in 74% of the patients, and was characterized by considerable intraindividual size difference, while diffuse hyperplasia was associated with more moderate and symmetric glandular enlargement. During follow-up averaging 4.5 years, the incidence of persistent or recurrent hypercalcemia was slightly higher after subtotal than after total parathyroidectomy (11 and 11%, vs. 9 and 7%). Biochemical and/or radiologic signs of parathyroid bone disease were present in 36 (44%) of the patients before neck exploration and normalized postoperatively in all but seven. The outcome of parathyroid surgery thus was favorable in uremic patients with hypercalcemic hyperparathyroidism.

Adolescent↗

PDGF-BB, but not PDGF-AA, stimulates calcium mobilization, activation of calcium channels and cell proliferation in cultured rat mesangial cells.

The effects of different isoforms of platelet-derived growth factor (PDGF) on cellular growth and on cytoplasmic Ca2+ levels in mesangial cells using a microfluorometric system and the calcium indicator FURA-2 were investigated. A rapid increase of cytoplasmic calcium in response to PDGF-BB was found and in the presence of 1.25 mM extracellular calcium, the resting level of cytoplasmic calcium following the initial peak was significantly increased compared with a calcium-free medium, but was completely attenuated with the calcium channel blocker verapamil (50 microM). PDGF-AA did not cause any increase in cytoplasmic calcium. In growth arrested MC PDGF-BB, but not PDGF-AA, also enhanced cell growth. It is concluded that cultured rat mesangial cells react to PDGF-BB but not to PDGF-AA with a rapid mobilization of intracellular calcium followed by subsequent activation of calcium channels and a stimulation of cell growth. A PDGF-BB driven mechanism for MC proliferation in inflammatory and metabolic glomerular diseases is suggested.

Animals↗