Ectopic production

M. Singler and D. Kaiser (1995). Ectopic production of guanosine penta- and tetraphosphate can initiate early developmental gene expression in Myxococcus xanthus. Genes Dev., 9, 1633-1644. 

With few exceptions, an increase in the activity or mass of an enzyme or isoenzyme is not specific or sensitive enough to be used for identifying the type of cancer or the specific organ involvement. An exception is PSA. PSA has mild protease activity and amino acid sequence homology with serine protease of the kallikrein family.It is expressed by normal, benign, hyperplastic, and cancerous prostate glands and minimally by other tissue. Until the application of PSA as a marker for prostate cancer, tumor enzymes had lost most of their popularity for use as cancer markers. Enzymes were used historically as tumor markers before the discovery of oncofetal antigens and the advent of monoclonal antibodies. The abnormalities of enzymes as a marker for cancer are either the expression of the fetal form of the enzyme (isozyme) or the ectopic production of enzymes. 

Rationale Patients with Cushing s syndrome caused by an ACTH-producing pituitary adenoma usually show suppression of cortisol with high-dose dexamethasone. Patients with Cushing s syndrome from other causes (adrenocortical adenoma, adrenocortical carcinoma, or ectopic production of ACTH) usually do not demonstrate any change in cortisol concentration. 

Overproduction of cortisol by hyperplastic adrenal cortices can result from oversecretion of ACTH (secondary hypercortisolism) due to a defect at the level of the pituitary or median eminence or to ectopic production of ACTH. The former condition is known as Cushing s disease and the latter as ectopic ACTH syndrome. In both conditions, the adrenal cortex functions normally and secretes cortisol in proportion to the level of ACTH. 

Primary hyperparathyroidism results from hyperplasia, adenoma, or carcinoma of the parathyroid glands and from ectopic production of the hormone by squamous cell carcinoma of the lung or by adenocarcinoma of the kidney. In about 10% of hyperparathyroidism, hyperplasia or tumors of the parathyroid glands occur due to familial disorders known as multiple endocrine neoplasia (MEN). MEN syndromes consist of three subtypes (I, IIA, IIB) and are... 

The first test used to determine the etiology of Cushing s syndrome is the plasma ACTH test. Plasma ACTH concentrations can be measured via RIA or IRMA. In the ACTH-dependent Cushing s syndromes, ACTH may be normal or elevated. Very high levels of ACTH favor ectopic production. ACTH values are low in ACTH-independent (adrenal) Cushing s syndrome. ACTH levels may appear artificially low in some ectopic ACTH-producing tumors because ACTH can be secreted as an active prohormone that is not detected by the assay. 

This patient presents with many of the classic findings of Cushing syndrome. Adrenal hyperplasia can be caused by excessive stimulation from ACTH (pituitary or ectopic production) or from a primary adrenal problem such as adenomas/ carcinomas. In addition to above symptoms, patients with Cushing syndrome are also at risk for osteoporosis and diabetes mellitus (DM). The diagnosis is confirmed with elevated cortisol levels after a dexamethasone suppression test. Treatment depends on the underlying etiology and is often surgical. 

Muller OA, von Werder K. Ectopic production of ACTH and corticotropin-releasing hormone (CRH). J Steroid Biochem Mol Biol 1992 43 403-8. 

Hyperphosphatasemia in patients with breast carcinoma usually denotes the presence of hepatic or skeletal metastases (C32, C35, Gl). Nathanson and Fishman (Nl) claimed that, in at least some patients with breast carcinoma, hyperphosphatasemia was due to the ectopic production of alkaline phosphatase by the tumor. Measurements of serum alkaline phosphatase values are of little use in monitoring the effects of endocrine ablation and other therapeutic agents (D14, Gl). 

These urea and electrolytes are typical of dilutional hyponatraemia. Her normal blood pressure and senim urea and creatinine concentrations exclude significant sodium depletion. The absence of oedema excludes a significant increase in her total body sodium. These results are characteristic of the. so-called syndrome of inappropriate aniidiuresis (SIAD) and arc due to secretion of AVP in response to non-osmotic stimuli. The ectopic production of AVP is extremely rare even in patients with malignant disease. 

The client has developed Cushing s syndrome as a result of an ectopic production of ACTH by a bronchogenic tumor. Which medication would the nurse anticipate the health-care provider prescribing ... 

Studies on the sub-units of human glycoprotein hormones in relation to reproduction have been reviewed. " One volume of a treatise on hormonal proteins and peptides has been devoted to thyroid hormones. The ectopic production of human chorionic gonadotrophin (hCG) and its a- and /J-sub-units has been discussed. ... 

Ectopic production of ACTH, for example by small cell lung carcinoma. 

In this context, the ectopic production of resveratrol could have positive effects on the enhancement of the nutritional value of several widely consumed fruits and vegetables. This chapter focuses on the latest findings regarding on resveratrol bioproduction in tomato (Solanum lycopersicum) fruits. 

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