The rapid low-dose (1 microgram) cosyntropin test in the immediate postoperative period: results in elderly subjects after major abdominal surgery

BACKGROUND

Recently the rapid low-dose (1 microgram) cosyntropin test has been found to be superior to the standard (250 micrograms) rapid cosyntropin test for evaluating the hypothalamic-pituitary-adrenal axis. Because the 1-microgram test has not been studied in postoperative patients, we evaluated the test after major abdominal surgery.

METHODS

We performed rapid 1-microgram cosyntropin tests in 20 patients aged 65 years or older immediately and 24 hours after uncomplicated elective abdominal surgery (group A) and in 10 patients who were suspected of having adrenal insufficiency after abdominal surgery (group B). Subsequently, 250 micrograms of cosyntropin was infused over 8 hours on 2 successive days in group B patients.

RESULTS

Ninety-five percent of group A patients had normal rapid 1-microgram cosyntropin test results immediately after surgery and 90% had normal test results 24 hours postoperatively. Six group B patients had abnormal rapid 1-microgram cosyntropin test results. Additional testing indicated primary adrenal insufficiency in 2 patients and central adrenal insufficiency in 1 patient; another patient probably had primary adrenal insufficiency and 2 patients appeared to be euadrenal. Four group B patients had normal rapid 1-microgram cosyntropin test results. After additional testing, 3 of these patients appeared to have normal adrenal function; 1 probably had primary adrenal insufficiency.

CONCLUSION

The rapid 1-microgram cosyntropin test accurately evaluated adrenal gland function in selected patients after uncomplicated surgery. The test, however, was difficult to interpret in unselected seriously ill postoperative patients. Therefore we recommend that postoperative patients with unexplained hypotension or other features suggestive of adrenal insufficiency who have random plasma cortisol levels less than 20 micrograms/dL be treated with glucocorticoids and the hypothalamic-pituitary-adrenal axis be studied by standard tests after recovery.

Serum parathyroid hormone-related protein levels during lactation

We measured parathyroid hormone-related protein (PTHrP) in the serum of 15 healthy women within three days of beginning breast-feeding and within one hour of completing nursing. A sensitive immunoradiometric assay that measures N-terminal PTHrP containing at least the first 74 amino acids was used. We found normal PTHrP values in all patients. Values one day before and two days after delivery in a hypoparathyroid woman who chose not to breast-feed were also normal. Since N-terminal PTHrP fragments of 1-36 amino acids or more are biologically active, we believe additional studies using sensitive PTHrP assays that measure smaller fragments and investigations performed under other conditions of breast-feeding are necessary before concluding that PTHrP does not have a role in calcium homeostasis in nursing mothers. Furthermore, additional studies in hypoparathyroid nursing mothers should be performed.

Postoperative acute adrenal failure caused by transient corticotropin deficiency

BACKGROUND

Acute adrenal insufficiency after a surgical procedure or trauma is rarely reported. In recent years, however, we have treated seven patients with acute primary adrenal insufficiency and three patients with secondary adrenal insufficiency who presented with shock after a surgical procedure or trauma. The standard cosyntropin test was misleading for the diagnosis of corticotropin deficiency.

METHODS

In this study we measured serum cortisol in patients older than 65 years who had unexplained hypotension after an abdominal surgical procedure. If the serum cortisol was less than 15 micrograms/dl, we performed 1 microgram and standard (250 micrograms) cosyntropin tests and measured thyroxine, thyrotropin, leutinizing hormone in all patients, and free testosterone in men.

RESULTS

We identified five (5%) of 105 patients after an operation who displayed evidence of corticotropin deficiency (i.e., serum cortisol < 15 micrograms/dl during hypotension, prompt hemodynamic improvement with glucocorticoid therapy, and normal response to standard dose cosyntropin). In these patients 1 microgram cosyntropin produced abnormal peak cortisol levels. These patients also had thyrotropin or leutinizing hormone deficiency. After recovery the low hormone levels improved or became normal.

CONCLUSIONS

Postoperative adrenal insufficiency, particularly that caused by transient corticotropin deficiency, is more common in patients than currently recognized. The 1 microgram cosyntropin test may be more sensitive than the standard test for identifying secondary adrenal insufficiency.

Subclinical hormone secretion by incidentally discovered adrenal masses

OBJECTIVE

To determine the frequency of subclinical hormone secretion in incidentally discovered adrenal masses.

DESIGN

We reviewed the radiologic reports of 1779 consecutive computed tomographic scans of the chest, abdomen, and pelvis.

SETTING

Regional referral medical center.

PATIENTS

Eighty-nine patients with abnormalities of one or both adrenal glands were identified. Patients with nonadrenal gland malignant neoplasms, primary aldosteronism, adrenal hemorrhage, and death or severe illness were not investigated. The final study group consisted of 26 patients with incidentally discovered adrenal masses.

MAIN OUTCOME MEASURES

Aldosterone secretion was assessed by measuring plasma renin activity and the plasma aldosterone concentration in patients with unexplained hypokalemia. We evaluated cortisol secretion by performing a 1-mg overnight dexamethasone suppression test and by measuring the corticotropin concentration at 8 AM by a sensitive method. In patients with low corticotropin values, we also measured the 24-hour urinary excretion of free cortisol and 17-ketosteroids and assessed diurnal variation by measuring plasma cortisol concentrations at 8 AM and 4 PM. Adrenal medullary function was studied by measuring urinary free catecholamines.

RESULTS

One patient had unrecognized primary aldosteronism, two patients had elevated free catecholamine excretion, and three patients (12%) had subclinical Cushing's syndrome.

CONCLUSION

Based on our observations and a review of the literature, we conclude that subclinical hormone secretion, especially cortisol secretion, is more common in patients with incidentally discovered adrenal masses than previously appreciated. Surgeons and anesthesiologists must be alert to the possibility that adrenal insufficiency or a hypertensive crisis may develop in the perioperative period in patients with incidentally discovered adrenal masses.

Reduced calcitriol requirements for treating hypoparathyroidism during lactation. A case report

We reduced the dose of calcitriol from 0.75 to 0.25 microgram/d to maintain low normal serum calcium levels in a hypoparathyroid woman during lactation. Calcitriol requirements quickly returned to 0.75 microgram/d when she discontinued breast-feeding. In her previous pregnancy, failure to reduce the dose of calcitriol resulted in serious hypercalcemia 11 days after she began breast-feeding. The changing requirement for calcitriol in our patient related directly to the falling level of estradiol. Although the cause or causes of diminished calcitriol requirements in hypoparathyroid women during lactation remains unclear, increased bone resorption promoted by low plasma estrogen levels may be an important mechanism. We conclude that the dose of calcitriol should be reduced during lactation and that both the hypoparathyroid mother and her infant should be carefully monitored to detect abnormal serum calcium levels.

Transient corticotropin deficiency in critical illness

We describe three critically ill patients who displayed indirect evidence of transient corticotropin deficiency. All these patients were elderly, were poorly nourished, and had unexplained hypotension intraoperatively or immediately postoperatively. During the hypotensive episodes, they had inappropriately low plasma cortisol levels (10, 12, and 6 micrograms/dl) and responded dramatically to the administration of glucocorticoids. A normal response to infusion of synthetic corticotropin excluded primary adrenal insufficiency. Two patients tested had low thyroxine levels without increased thyrotropin concentrations and depressed levels of gonadotropins. In all three patients, the dose of glucocorticoids was successfully tapered and then discontinued. After recovery, serum thyroxine levels increased, gonadotropins reverted to normal concentrations, and the administration of metyrapone to two patients demonstrated normal hypothalamic-pituitary-adrenal function. Cortisol levels of less than 15 micrograms/dl in critically ill patients suggest the presence of adrenal insufficiency. The infusion of synthetic corticotropin may not exclude adrenal insufficiency attributable to corticotropin deficiency. If direct tests of corticotropin reserve are impractical, treatment with glucocorticoids is warranted.

Spurious elevation of plasma immunoreactive adrenocorticotropic hormone in cyclic Cushing's syndrome

We studied a 40-year-old woman with cyclic Cushing's syndrome who demonstrated abnormal high-dose dexamethasone suppression and metyrapone stimulation tests. These results, associated with persistent elevations of plasma adrenocorticotropic hormone (ACTH) levels, suggested ectopic secretion of ACTH. Surprisingly, an adrenal adenoma with atrophy of the contralateral adrenal gland was found at exploratory laparotomy. Subsequent ACTH determinations that extract ACTH from the plasma before assay suggested that the apparent increase in ACTH concentration in our routine assay was due to the presence of an interfering substance(s). We conclude that the diagnosis of Cushing's syndrome continues to depend on a battery of adrenal function tests and radiographic procedures and recommend that measurements of ACTH be performed only after extraction of ACTH from specimens.

Thyroid gland size in pregnancy. An ultrasound and clinical study

We estimated the size of the thyroid gland by palpation and measured thyroid gland volume with ultrasound in the immediate postpartum period and six months after delivery in 16 women. The 13% reduction in the mean thyroid gland volume detected six months after delivery implied that the thyroid gland enlarges slightly during pregnancy. Physical examination, however, did not detect any goiters during the immediate postpartum period and did not identify a change in thyroid gland size six months after delivery. The thyroid gland enlargement that occurs during pregnancy is not large enough to be detected by physical examination. We urge physicians to discard the commonly held notion that goiter frequently develops during pregnancy.

Rapid loss of lactate dehydrogenase isoenzyme activity in serum by cold-induced formation of immunoglobulin G-lactate dehydrogenase complex

Lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum from a patient recovering from a myocardial infarction was extremely unstable when stored at 0 degree C. The activity of each LD isoenzyme except LD-1 decreased by at least 40% when serum was stored at 0 degree C for 4 h. The patient's erythrocyte LD activity had normal stability at lower temperatures, but LD from other sources, when added to the patient's serum, rapidly lost activity at 0 degree C. The patient's serum contained an immunoglobulin G that combined--at 0 degree C but not at 21 degrees C--primarily with LD isoenzymes containing one or more M subunits. Because this immunoglobulin-LD complex has no enzyme activity, we used 125I-labeled purified LD to study formation of the complex. NAD+ blocked the formation of immunoglobulin-LD complex but could not dissociate the complex and restore the LD activity.

Rapid loss of lactate dehydrogenase isoenzyme activity in serum by cold-induced formation of immunoglobulin G-lactate dehydrogenase complex

Lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum from a patient recovering from a myocardial infarction was extremely unstable when stored at 0 degree C. The activity of each LD isoenzyme except LD-1 decreased by at least 40% when serum was stored at 0 degree C for 4 h. The patient's erythrocyte LD activity had normal stability at lower temperatures, but LD from other sources, when added to the patient's serum, rapidly lost activity at 0 degree C. The patient's serum contained an immunoglobulin G that combined--at 0 degree C but not at 21 degrees C--primarily with LD isoenzymes containing one or more M subunits. Because this immunoglobulin-LD complex has no enzyme activity, we used 125I-labeled purified LD to study formation of the complex. NAD+ blocked the formation of immunoglobulin-LD complex but could not dissociate the complex and restore the LD activity.

Peripheral resistance to thyroid hormone in a family: heterogeneity of clinical presentation

We describe a family with thyroid hormone resistance. Juvenile Graves disease was diagnosed in the propositus, an 8-month-old boy. He was initially given propylthiouracil, and at 22 months of age underwent subtotal thyroidectomy. A diagnosis of hyperthyroidism was made in a younger sister at 3 months of age. Because of the unusual occurrence of juvenile Graves disease in two siblings, we evaluated the parents. The mother was euthyroid on physical examination and by thyroid hormone measurements. The father, although clinically euthyroid, had markedly elevated thyroid hormone values. In the three affected members, serum thyrotropin concentrations and results of thyrotropin-releasing hormone infusion tests were inappropriate for the elevated serum thyroid hormone levels. The father was given increasing doses of triiodothyronine. Complete suppression of TRH-induced TSH release did not occur until a daily dose of 300 micrograms triiodothyronine was administered. Furthermore, this large dose of T3 did not produce clinical evidence of hyperthyroidism or result in changes in his systolic ejection time intervals. This family therefore had the unusual feature of clinical heterogeneity. The two children had mainly pituitary resistance to thyroid hormone and were hyperthyroid; the euthyroid father, on the other hand, had generalized tissue resistance to thyroid hormone.

Interference in a chromogenic alpha-amylase assay caused by dye-labeled oligosaccharide-induced precipitation of lipoprotein

We examined the mechanism by which hypertriglyceridemia interferes with the Roche Diagnostics "Amylochrome" procedure for measurement of amylase in lactescent samples with normal and above-normal amylase activity. The serum blank recommended in the Amylochrome protocol to compensate for lactescence remains inappropriately turbid, compared with the test, and is partly responsible for the underestimation of amylase activity. Other major interference is seen when lipoprotein in hyperlipemic samples with above-normal amylase activity reacts with the soluble oligosaccharide-triazinyl dye product of the Amylochrome assay to form a flocculent blue precipitate. The formation of this precipitate in the test, and its removal, diminish lactescence due to lipemia, an effect that cannot be matched by any manipulation of a serum blank procedure. Oligosaccharide-dye product is removed as a component of the precipitate.

Interference in a chromogenic alpha-amylase assay caused by dye-labeled oligosaccharide-induced precipitation of lipoprotein

We examined the mechanism by which hypertriglyceridemia interferes with the Roche Diagnostics "Amylochrome" procedure for measurement of amylase in lactescent samples with normal and above-normal amylase activity. The serum blank recommended in the Amylochrome protocol to compensate for lactescence remains inappropriately turbid, compared with the test, and is partly responsible for the underestimation of amylase activity. Other major interference is seen when lipoprotein in hyperlipemic samples with above-normal amylase activity reacts with the soluble oligosaccharide-triazinyl dye product of the Amylochrome assay to form a flocculent blue precipitate. The formation of this precipitate in the test, and its removal, diminish lactescence due to lipemia, an effect that cannot be matched by any manipulation of a serum blank procedure. Oligosaccharide-dye product is removed as a component of the precipitate.

Enzymatic iodination of Sindbis virus proteins

Sindbis virus was iodinated by using the enzyme lactoperoxidase, an iodination technique which labels only surface proteins. By this technique, the two viral glycoproteins are labeled, and the internal viral protein is not. The two glycoproteins are iodinated to strikingly different extents. This difference in susceptibility to iodination apparently is due to the position or conformation of the glycoproteins in the envelope spikes of the virion and not to differing contents of tyrosine, the amino acid substrate of lactoperoxidase. Both viral glycoproteins are iodinated by lactoperoxidase on the surface of Sindbis-infected chicken cells. Here, as in the virion, the glycoproteins are iodinated unequally, with the smaller glycoprotein again being preferentially iodinated. Another virus-specific protein found in large amounts in infected cells, and from which the preferentially iodinated virion glycoprotein is produced by a proteolytic cleavage, is not iodinated by lactoperoxidase. Thus it appears that the viral glycoproteins are present on the cell surface and that the precursor protein is not.

Partial purification and properties of the pyruvate-uridine diphospho-N-acetylglucosamine transferase from Staphylococcus epidermidis

A method for the partial purification of the pyruvate-uridine-diphospho-N-acetylglucosamine transferase from Staphylococcus epidermidis is presented. Some properties of the enzyme are discussed.

Partial purification and some properties of the uridine diphospho-N-acetylglucosamine-enolpyruvate reductase from Staphylococcus epidermidis

A method for the partial purification of the uridine diphospho-N-acetylglucosamine-enolpyruvate reductase from Staphylococcus epidermidis is presented. Some properties of the enzyme, including its dependence on monovalent cation and flavine adenine dinucleotide, are discussed.

Appearance of muramic lactam during cortex synthesis in sporulating cultures of Bacillus cereus and Bacillus megaterium

Evidence is presented for the appearance of muramic lactam during the late stages of sporulation at about the same time dipicolinic acid synthesis occurs.

How penicillin kills bacteria: progress and problems

Penicillins and cephalosporins are specific inhibitors of the biosynthesis of bacterial cell walls. This discovery was first made in 1957 and was based on two observations. First, penicillins induced the formation of protoplasts or spheroplasts in bacteria (organisms in which the cell wall has been lost or weakened) (Lederberg 1957). Secondly, a uridine nucleotide accumulated in Staphylococcus aureus and other bacteria inhibited by penicillin which had a striking relationship to the composition of the cell wall (Park & Strominger 1957). It was therefore suggested that this nucleotide was an activated precursor of the wall. Over the next decade, a great deal of work was carried out in order to elucidate the structure of the bacterial cell wall and the mechanism of its biosynthesis from the uridine nucleotides and other precursors (reviewed by Strominger 1970; Strominger & Ghuysen 1967; Ghuysen 1968). It was demonstrated that interpeptide cross-links were an important structural feature of the wall. Several kinds of experiments carried out with whole cells indicated that the final step in cell wall synthesis, the crosslinking reaction catalysed by a transpeptidase, was the site of action of penicillin (Wise & Park 1965; Tipper & Strominger 1965 a , b , 1968). Finally, in 1966, the transpeptidase catalysing this cross-linking reaction was obtained in a cell-free system and shown to be a penicillin-sensitive enzyme (Izaki, Matsuhashi & Strominger 1966, 1968). The history of these developments has been reviewed elsewhere (Strominger 1970), and in the present paper, attention will be focused on recent studies of the penicillin-sensitive transpeptidase and other penicillinsensitive activities found in bacterial cell membranes. First, however, it is necessary to describe briefly the structure of the cell wall of bacteria and the nature of the inhibited reactions. The walls of bacteria consist of glycan strands in which two sugars, acetylglucosamine (X) and acetylmuramic acid (Y), strictly alternate (figure 1). Four such glycan strands are represented in figure 1. The acetylmuramic acid residues of the polymer are substituted by a tetrapeptide (represented in the figure by open circles). The peptidoglycan strand (i.e., the glycan substituted by the tetrapeptide) are cross-linked to one another by means of an interpeptide bridge which is to some extent a genus-specific character­istic. In the genus Staphylococcus aureus , the interpeptide bridge is a pentaglycine chain (represented in figure 1 by the closed circles) which extends from the carboxyl group on the terminal D-alanine residue of the tetrapeptide to the ∊-amino group of lysine, the third amino acid in the tetrapeptide chain. The wall of S . aureus is a very tightly knit structure in that virtually every peptide subunit is cross-linked to another subunit by means of this interpeptide bridge. Penicillins and cephalosporins are specific inhibitors of the reaction in which the cross-link is actually formed. This step is the last reaction in wall synthesis.