Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The secretory activity of parathyroid glands in rats was stimulated by decreasing the serum Ca++ concentration through constant intravenous infusion of EGTA. The morphometric analysis of the nuclear and cytoplasmic volume and of the surface area of the rough endoplasmic reticulum, Golgi complex, secretory granules and plasma membrane revealed a membrane shift from secretory granules and Golgi complex to the plasma membrane within 1 hr of calcium depression. Subsequently, between 1 and 3 hr of calcium depression, the membrane shift was from the plasma membrane to the Golgi complex. It is considered likely that these membrane shifts are related to a rise in release of parathyroid hormone by exocytosis and a subsequent increase in retrieval of plasma membrane by endocytosis--probably through the compartment of coated pits and coated and uncoated vesicles.
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PMID:Quantitative aspects of membrane shifts in rat parathyroid cells initiated by decrease in serum calcium. 623 79

Rats fed a diet deficient in both vitamin D and Ca2+ exhibited a greater depression of the renal parathyroid hormone (PTH)-dependent adenylate cyclase than was observed in rats fed diets deficient in either vitamin D or calcium. Total serum Ca2+ was decreased from a control level of 11.2 mg/dl to 8.5 mg/dl in rats fed the diet deficient in calcium alone, and to 5.4 mg/dl in rats fed the diet deficient in vitamin D. Serum calcium was decreased further to 4.3 mg/dl in rats fed the diet deficient in both vitamin D and Ca2+. Serum immuno-reactive PTH was significantly elevated over control levels when rats were fed the test diets; however, there were no significant differences between the elevated levels in the three experimental groups. Repletion of rats deficient in vitamin D only with a single oral dose of 3200 I.U. vitamin D-2 resulted in restoration of serum calcium to normal levels, a return of serum PTH to the control state, and an associated increase in PTH-dependent adenylate cyclase activity to the control level by 72 h. Repletion of rats deficient in both vitamin D and Ca2+ with the same dose of vitamin D-2 raised serum Ca2+ to 7.2 mg/dl by 72 h, but did not cause a reduction in circulating PTH, nor did it result in any significant improvement in the responsiveness of the membrane adenylate cyclase to PTH. These results suggest that elevated PTH is a factor in the down regulation of the PTH-dependent adenylate cyclase, but do not rule out a role for calcium as a regulatory factor.
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PMID:Renal parathyroid hormone-dependent adenylate cyclase activity after repletion of vitamin D-deficient rats with vitamin D-2. 625 4

Experiments were conducted on laying and nonlaying hens from genetically selected lines that produce thick (TK) or thin (TN) eggshells. At 44 weeks of age, TK layers exhibited significantly higher total plasma calcium concentrations than TN layers. Total plasma calcium concentrations were not significantly different between TK and TN layers at 80 weeks of age, reflecting an effect of aging on total plasma calcium. Intravenous injections of ethyleneglycol-bis-(B-aminoethylether-N,N'-tetraacetic acid (EGTA) were administered to TK and TN layers at 44 weeks of age and to TK and TN layers and nonlayers at 80 weeks of age. EGTA is a calcium chelating agent that creates hypocalcemia when injected intravenously. Laying hens of both lines and at both ages exhibited a similar degree of hypocalcemia during EGTA injections, and a similar rate of recovery to normocalcemia was noted after cessation of EGTA administration. Nonlayers were unable to recover from the EGTA-induced hypocalcemia. Because the pattern of calcium depression and recovery during and after the EGTA challenge has been shown to be associated with the capacity of parathyroid hormone-sensitive target tissues to buffer blood ionized calcium, it was concluded that the capacity to buffer ionized calcium by these target tissues is similar in TK and TN layers. However, nonlayers have a restricted capacity to buffer blood ionic calcium.
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PMID:Blood ionic calcium responses of hens from thick-shell and thin-shell lines to ethyleneglycol-bis-(B-aminoethylether)-N,N'-tetraacetic acid injections. 642 53

In order to determine the effects of parathyroid hormone on bone formation, mean wall thickness (MWT) of trabecular bone packets was measured on transilial undecalcified bone biopsies from 26 patients (14 females and 12 males) with primary hyperparathyroidism (HPT). Mean value of MWT in HPT patients (45.2 +/- 5.8 microns) was found to be significantly lower than in 35 controls (50.1 +/- 8.5 microns) (p less than 0.001). This difference is due to a significant reduction of MWT in HPT females before 50 years of age (46.0 +/- 2.3 microns) when compared with controls (56.2 +/- 7.1 microns; p less than 0.05), whereas there is no significant difference of average MWT in males of any age or in females after 50. These reductions of MWT could explain the rarefaction of spongy bone previously noticed in HPT females younger than 50 years. Furthermore, because of the mild depression of the osteoblastic activity measured by tetracycline double-labeling in HPT, the osteoblastic formation period was determined to be shortened in females before 50 years, and lengthened in females after 50 years of age and in males of any age. This could explain the anabolic effects of 1-34 hPTH fragment on trabecular bone volume in postmenopausal osteoporosis.
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PMID:Effects of parathyroid hormone on remodeling of iliac trabecular bone packets in patients with primary hyperparathyroidism. 706 20

Permanent hypocalcemia complicating thyroidectomy is a rare complication, whereas transient post-thyroidectomy hypocalcemia occurs frequently. Ten patients were studied in an attempt to elucidate the underlying mechanisms. An early and transient postoperative rise in calcitonin (CT) corresponding to a decline in calcium levels was demonstrated. Though there was no significant depression of parathyroid hormone (PTH) levels, the failure of the parathyroids to respond to hypocalcemic stimuli suggests a degree of at least transient parathyroid insufficiency. Transiently elevated CT levels appear to play a significant role in the commonly observed early, transient post-thyroidectomy hypocalcemia following subtotal and total thyroidectomy.
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PMID:The role of calcitonin and parathyroid hormone in the pathogenesis of post-thyroidectomy hypocalcemia. 723 Nov 95

A series of six experiments was conducted to investigate the effects of Mg deficiency in the young rat on parathyroid hormone (PTH) activity and on response to parathyroid extract (PTE) and to endogenously produced PTH stimulated by dietary Ca deficiency. Major criteria employed were 45Ca release from pre-labeled bone and urinary excretion of cAMP. Mg deficiency was accompanied by lowered 45Ca mobilization and urinary cAMP excretion, indicating either a depression in PTH secretion or tissue insensitivity to it. Administration of PTE resulted in equivalent increases in 45Ca mobilization irrespective of Mg status but increased cAMP excretion only in Mg-adequate animals, thus indicating a depressed sensitivity of kidney to PTH in the Mg-deficient animal. In vitro response of kidney cortex from Mg-deficient animals to PTE added to incubation medium indicated no defect in the adenyl cyclase system. Endogenous stimulation of PTH by low Ca diet increased cAMP in Mg-adequate animals but not in rats with pre-existing Mg deficiency. Mg deficiency did not reduce cAMP previously stimulated by Ca deficiency.
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PMID:Effect of magnesium deficiency on rat bone and kidney sensitivity to parathyroid hormone. 740 Aug 50

This study reports the changes observed in bone-formation dynamics at the cell, tissue and organ level in cortical bone in four standardization research colony-raised male Beagles that were exposed to 0.7 mg of lead acetate per day for 6 months, followed by a 6-month period when no lead acetate was given. Four similar age-sex matched Beagles of the same origin served as controls. Tissue and blood lead levels were measured. Biochemical and hematological analysis were carried out on a monthly basis. Plasma levels of immunoreactive parathyroid hormone were measured. In the absence of any alteration of the dogs' internal milieu, following 6-months exposure to lead there was a decrease in bone formation at the cell (70 percent), tissue (66 percent) and organ (66 percent) levels. Six months after the lead exposure was interrupted, bone formation returned to normal (93 percent at tissue and 100 percent at organ levels), but there was still some depression of activity at the cell level (70 percent). It is not known whether that cell-level depression of activity is due to persistent enzymatic inhibition following the 6-months exposure or whether it is due to the fact that the cell continued to operate in a micro-environment in which tissue levels of lead are elevated, or both.
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PMID:Haversian bone-remodelling rates in the beagle after cessation of exposure to chronic low doses of lead. 744 Oct 93

Primary hyperparathyroidism is a not uncommon disease in the elderly. A prevalence of 3% for women and 1% for men is reported in subjects aged 65 years and over. Routine serum calcium determination and parathyroid hormone radioimmuno-assay allow to make an early diagnosis in still asymptomatic subjects. In the elderly the clinical features of the disease are often aspecific presenting with psychiatric and/or neuromuscular and/or cardiovascular disorders. This report refers to a 75 year-old woman admitted to our Department with a suspicion of senile dementia. She was affected by loss of memory, hallucinations, nausea, loss of appetite, mild polydipsia and polyuria. The patient was dependent in one activity of daily living (Index of Independence in Activities of Daily Living, ADL) and partially dependent in instrumental activities of daily living (Instrumental Activities of Daily Living Scale, IADL). The Short Portable Mental Status Questionnaire (SPMSQ) and the Geriatric Depression Scale (GDS) showed mild mental impairment and mild depression. Routine biochemical screening revealed a significant hypercalcemia. Parathormon assay and parathyroid scintigram were performed to confirm the diagnosis of primary hyperparathyroidism. After treatment of dehydratation and hypercalcemia, parathyroidectomy was performed: a single parathyroid adenoma was found and removed. On discharge the patient was lucid and able to carry out all ADLs and IADLs.
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PMID:[Neuropsychologic symptoms of primary hyperparathyroidism in the elderly. Report of a clinical case]. 773 70

Proteolytic enzymes, lipase, kinins, and other active peptides liberated from the inflamed pancreas convert inflammation of the pancreas, a single-organ disease of the retroperitoneum, to a multisystem disease. Adult respiratory distress syndrome, in addition to being secondary to microvascular thrombosis, may be the result of active phospholipase A (lecithinase), which digests lecithin, a major component of surfactant. Myocardial depression and shock are suspected to be secondary to vasoactive peptides and a myocardial depressant factor. Coagulation abnormalities may range from scattered intravascular thrombosis to severe disseminated intravascular coagulation. Acute renal failure has been explained on the basis of hypovolemia and hypotension. The renin-angiotensin alterations in acute pancreatitis (AP) as mediators of renal failure need to be studied. Metabolic complications include hypocalcemia, hyperlipemia, hyperglycemia, hypoglycemia, and diabetic ketoacidosis, of which hypocalcemia has been long recognized as an indicator of poor prognosis. The pathogenesis of hypocalcemia is multifactorial and includes calcium-soap formation, hormonal imbalances (e.g., parathyroid hormone, calcitonin, glucagon), binding of calcium by free fatty acid-albumin complexes, and intracellular translocation of calcium. Subcutaneous fat necrosis, arthritis, and Purtscher's retinopathy are rare. The various prognostic criteria of AP and other associated laboratory abnormalities are manifestations of systemic effects. Early recognition and appropriated management of these complications have resulted in improved prognosis of severe AP.
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PMID:Acute pancreatitis: a multisystem disease. 804 85

An 85-year-old man who presented with depression and lethargy was found to have hypercalcemia, normal phosphorous, and low-normal intact parathyroid hormone level. Work-up revealed no evidence of a malignant or inflammatory process. However, 24-hour urinary calcium excretion was increased, 1,25 dihydroxy (OH2) vitamin D3 level was elevated, and angiotensin-converting enzyme (ACE) level was twice normal. The patient responded to a trial of steroids and his 1,25-OH2 vitamin D3 and ACE levels decreased to within normal limits. The patient has remained eucalcemic on low-dose steroids.
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PMID:Hypercalcemia associated with an elevated 1,25 dihydroxy vitamin D3 level and an elevated angiotensin-converting enzyme level in a patient without evidence of sarcoidosis or malignancy. 805 95


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