Application of serum nicotine and plasma cotinine concentrations to assessment of nicotine replacement in light, moderate, and heavy smokers undergoing transdermal therapy.

As part of a clinical trial investigating the level of nicotine replacement with different doses of transdermal therapy for smoking cessation, peak and trough serum nicotine and plasma cotinine concentrations were measured in 70 subjects while they were actively smoking (baseline) and daily for 6 consecutive inpatient days while they were receiving transdermal nicotine. Subjects were randomly assigned to a daily 24-hour patch delivering a transdermal nicotine dose of 0, 11, 22, or 44 mg and stratified by self-reported smoking rate as either light (10-15 cigarettes per day), moderate (16-30 cigarettes per day), or heavy (>30 cigarettes per day). Steady-state concentrations of nicotine and cotinine were attained in 1 and 3 days, respectively, at all doses and were independent of baseline smoking rate. Mean percentage replacement of nicotine was calculated by dividing steady-state peak nicotine or cotinine concentrations by their respective baseline concentrations. Significant underreplacement occurred in subjects receiving the 11 mg/day patch regardless of baseline smoking rate. Underreplacement also occurred in moderate and heavy smokers receiving 22 mg/day and in light smokers at this same dose. Complete replacement occurred only in subjects receiving the 44 mg/day patch. These results have several implications for transdermal nicotine therapy. First, with the higher nicotine and cotinine levels observed with heavier smoking, it is inherent that one size does not fit all, and there is a need to consider more individualization of dosage for nicotine patch therapy. Second, there is substantial underreplacement with the 22 mg/day dose in moderate to heavy smokers and in some light smokers. Third, even with twice the usual dose (i.e., 44 mg/day), there was no accumulation of either nicotine or cotinine. Plasma cotinine levels after achievement of steady state (i.e., after 3 days of patch therapy) can be collected at any time and used to calculate percent replacement using baseline levels.

Application of urine nicotine and cotinine excretion rates to assessment of nicotine replacement in light, moderate, and heavy smokers undergoing transdermal therapy.

As part of a clinical trial investigating the level of nicotine replacement with different doses of transdermal therapy for smoking cessation, urine excretion rates of nicotine and cotinine were measured in 70 subjects while they were actively smoking (baseline) and for 6 consecutive inpatient days while they were receiving transdermal nicotine therapy. Subjects were stratified according to baseline smoking rate as light (10-15 cigarettes per day), moderate (16-30 cigarettes per day), or heavy (>30 cigarettes per day) smokers and randomly assigned to a daily 24-hour patch delivering a transdermal nicotine dose of 0, 11, 22, or 44 mg. Steady-state excretion rates of nicotine and cotinine were attained in 2 and 3 days, respectively, at all doses and were independent of smoking rate. Percentage replacement of nicotine was calculated by dividing steady-state nicotine or cotinine excretion rates by their respective baseline excretion rates. Significant underreplacement occurred with the 11-mg/day dose, particularly in moderate and heavy smokers (<50%). At a dose of 22 mg/day, nicotine replacement was still <100% in the majority of subjects. Only at a dose of 44 mg/day did mean replacement exceed 100% regardless of baseline smoking rate.

Urinary free cortisol and cortisone determined by high performance liquid chromatography in the diagnosis of Cushing's syndrome.

To determine the efficacy of cortisol and its metabolite, cortisone, measured simultaneously by high performance liquid chromatography (HPLC) in the diagnosis of Cushing's syndrome, we retrospectively reviewed the histories of 29 surgically proven Cushing's syndrome patients (20 Cushing's disease, 5 ectopic ACTH syndrome, and 4 adrenal Cushing's syndrome) and 6 patients with exogenous Cushing's syndrome. These 35 patients had urinary free cortisol determined by both HPLC and competitive binding methods. The efficacy of the HPLC assay using cortisol alone was equivalent to that of the competitive binding assay; 22 of 29 (76%) patients had increased cortisol. Cortisone also aided in the diagnosis; 25 of 29 (86%) had increased cortisone. Twenty-seven of the 29 (93%) patients had either both cortisone and cortisol (n = 19) or at least 1 of the 2 (n = 8) increased. All 6 patients with exogenous Cushing's syndrome had suppressed urinary free cortisol, cortisone, and the presence of prednisone and prednisolone. In the competitive binding assay, all exogenous Cushing's patients had falsely increased cortisol results. In conclusion, urinary free cortisol plus cortisone determined simultaneously by HPLC added a new dimension to the diagnosis of Cushing's syndrome. It should be considered when exogenous Cushing's syndrome is suspected or when only one urinary cortisol test is allowed to be ordered.

Incremental value of the leukocyte differential and the rapid creatine kinase-MB isoenzyme for the early diagnosis of myocardial infarction.

OBJECTIVE: To test whether automated measurements of cortisol-induced changes in the leukocyte differential can provide an early marker of myocardial infarction, especially when combined with the rapid creatine kinase-MB isoenzyme. DESIGN: A prospective, blinded study of these measurements at the time of initial assessment in the emergency department. SETTING: Large multispecialty clinic hospital. PATIENTS: 511 consecutive patients presenting to the emergency department with chest pain. One hundred twenty-seven patients with infection, trauma, or metastatic cancer or receiving myelosuppressive or glucocorticoid therapy were excluded. MEASUREMENTS: Automated leukocyte differentials, rapid creatine kinase-MB levels, cortisol levels, and routine clinical measurements. RESULTS: Of 69 patients with myocardial infarction, only 39% had diagnostic electrocardiographic ST-segment elevation. ST-segment elevation had a specificity of 99% and a positive predictive value of 93%. A relative lymphocytopenia (lymphocyte decrease < 20.3%) or elevated rapid creatine kinase-MB level (> 4.7 ng/mL) was more sensitive than ST-segment elevation (sensitivities of 58% and 56%, respectively) but less specific (specificities of 91% and 93%, respectively). The presence of both a relative lymphocytopenia and an elevated rapid creatine kinase-MB level had a sensitivity of 44%, a specificity of 99.7%, and a positive predictive value of 97% (95% Cl, 80% to 99%). Both a relative lymphocytopenia and an elevated rapid creatine kinase-MB level were independent (P < 0.001) predictors of infarction in patients without ST-segment elevation. If myocardial infarction was suspected by the presence of both abnormal markers or ST-segment elevation, the sensitivity for early diagnosis increased from 39% (ST elevation alone) to 65% (Cl, 52% to 76%); the specificity was 99%; and the positive predictive value was 94% (Cl, 82% to 98%). CONCLUSIONS: The presence of both a relative lymphocytopenia and an elevated rapid creatine kinase-MB level was an accurate early marker of myocardial infarction that appeared to improve the sensitivity of early diagnosis compared with that of ST-segment elevation alone.

Serum nicotine and cotinine levels during nicotine-patch therapy.

We related serum nicotine and cotinine levels while subjects were smoking their usual numbers of cigarettes to levels while wearing a nicotine patch under carefully controlled, smoke-free conditions in a clinical research center. Twenty-four volunteers who needed intensive treatment for severe nicotine dependence were admitted to the clinical research center and were treated with a 22 mg transdermal nicotine patch each day and an intensive smoking-cessation program. Serum nicotine and cotinine levels, withdrawal symptoms, and hours and quality of sleep were noted. The steady-state serum nicotine and cotinine levels produced with the nicotine patch were lower than those observed when the subjects were smoking. Mean nicotine and cotinine levels were inversely related to mean withdrawal scores for the first 6 days. A fixed dose of transdermal nicotine will not be effective for all smokers. Individualization of therapy should be based on objective biologic measures such as serum cotinine and subjective assessment of withdrawal relief.

Effect of megestrol acetate on the human pituitary-adrenal axis.

A few previous reports have suggested that megestrol acetate, a synthetic progestational agent frequently used as an antineoplastic drug, suppresses serum cortisol concentrations in humans. To explore this concept further, we prospectively performed several measurements of the pituitary-adrenal axis in patients receiving megestrol acetate (160 or 800 mg/day). The data from these evaluations demonstrate that megestrol acetate reversibly decreases serum cortisol concentrations in humans and that this effect seems to originate from a suppression of the pituitary-adrenal axis. Additional studies should be conducted to determine the implications of the low levels of serum cortisol.

Biochemical evaluation of adrenal dysfunction: the laboratory perspective.

In this study, we reviewed the diagnostic efficiency of laboratory tests that are performed for assessment of patients with Cushing's syndrome or adrenal insufficiency. Baseline laboratory data from patients subsequently diagnosed with adrenal dysfunction were analyzed for tests performed between 1987 and 1989 at our institution. Results were analyzed for 36 patients diagnosed with pituitary-dependent Cushing's syndrome, 15 with ectopic Cushing's syndrome, 12 with adrenal-dependent Cushing's syndrome, 20 with primary adrenal insufficiency, and 7 with secondary adrenal insufficiency. Tests reviewed were plasma cortisol, plasma corticotropin, urinary free cortisol, urinary 17-ketosteroids, urinary ketogenic steroids, low-dose and high-dose dexamethasone suppression, and metyrapone stimulation. Our findings suggest that a substantial proportion of diagnoses could be based on the results of three tests--plasma corticotropin, plasma cortisol, and urinary free cortisol. We present a nomogram that combines the results of plasma corticotropin and plasma cortisol testing to enhance the diagnostic efficiency of these tests.

Ovine corticotropin releasing hormone stimulation test: normal value study.

We determined the pituitary-adrenal response to 1 microgram/kg of ovine corticotropin releasing hormone (oCRH) administered as an intravenous bolus injection in 50 normal subjects. Brief facial flushing was noted in 44% of the subjects; no other side effects were reported. Plasma corticotropin levels increased from a median of 30.2 pg/ml at baseline to a median peak level of 77.8 pg/ml after administration of oCRH; the peak response occurred at the 30- to 45-minute or the 45- to 60-minute time point. Plasma cortisol levels increased from a median of 10.8 micrograms/dl at baseline to a median peak level of 22.0 micrograms/dl after administration of oCRH; the peak response occurred at the 45- to 60-minute time point. Plasma beta-endorphin levels increased from a median of 9.5 pg/ml at baseline to a median peak level of 23.0 pg/ml after administration of oCRH; the peak response occurred at the 15- to 30-minute or the 30- to 45-minute time point. The responsiveness to oCRH was unaffected by age, sex, or body mass index of the subjects.

Recent developments in the diagnosis and treatment of pheochromocytoma.

The investigation and management of pheochromocytoma have been of special interest at the Mayo Clinic since 1926, when Dr. C. H. Mayo successfully removed an adrenal tumor. Recent clinical developments include the detection of asymptomatic paroxysms of hypertension by 24-hour ambulatory monitoring, detailed characterization of catecholamine cardiomyopathy by echocardiography, and further experience with Carney's triad and other polyglandular and multiple neoplasia syndromes associated with pheochromocytoma. Refinement in interpretation of catecholamine measurements and the development of radionuclide scanning with m-[131I]iodobenzylguanidine, computed tomography, and magnetic resonance imaging have greatly enhanced our diagnostic acumen. Developments in antihypertensive drug therapy and chemotherapy have improved our management of cathecholamine hypersecretion and tumor growth, respectively, in inoperable patients and in the preparation of patients for anesthesia and surgical treatment. Flow cytometry to detect abnormal DNA histograms may prove particularly useful in predicting the malignant nature of the tumors.

Estrogen and progesterone receptors in meningiomas: comparison of nuclear binding, dextran-coated charcoal, and immunoperoxidase staining assays.

We studied the status of estrogen (ER) and progesterone (PR) receptors in meningiomas removed from 52 patients, comparing dextran-coated charcoal (DCC), nuclear binding (NB), and immunoperoxidase (IP) assays. Each of the assays was performed independently by investigators well-experienced with these assays. The NB assay is a new assay that measures functional steroid receptors--that is, the activation of the receptor and its binding to the nucleus. The assay is very sensitive and requires a relatively small amount of tissue as compared with the DCC assay. In agreement with data from other studies. PR were detected in most meningiomas by all 3 methods: in 69% of the cases by NB, in 76% by DCC, and in 89% by IP. ER were detected in only a few cases: in 33% by NB, in 2% by DCC, and in none by the IP assay. The agreement for PR sites was 62% for all 3 assays; it was 66% between the NB and DCC assays, 67% between the NB and IP assays, and 86% between the DCC and IP assays. Of 26 cases that were positive by the DCC assay, 6 (23%) were negative by NB. The overall agreement for all three ER assays was 65%. The data suggest that the majority of meningiomas contain high-affinity receptors for progesterone, that estrogen receptors are present in only a few meningiomas, and that some of these estrogen and progesterone receptors appear to be functional.

The effects of synthetic alpha-subunit peptides on thyroid-stimulating immunoglobulin activity.

Synthetic peptides, representing specific portions of the alpha-subunit of the human glycoprotein hormones, can inhibit both the binding of labeled TSH to thyroid membranes and adenylate cyclase stimulation by TSH in vitro. The same synthetic peptides (alpha 26-46 and alpha 31-45) significantly (P less than 0.05) inhibited the adenylate cyclase-stimulating activity of thyroid-stimulating immunoglobulins (TSI) from 10 patients with hyperthyroid Graves' disease. Peptide alpha 26-46 was the most potent, resulting in 79.1 +/- 8.8% (+/- SE) inhibition at 133 micrograms/mL, while peptide alpha 31-45 inhibited TSI activity by 36.3 +/- 5.2%. Peptides alpha 61-75 and alpha 81-92, that had only minimal ability to inhibit TSH-mediated cAMP generation, did not significantly inhibit TSI activity. The inhibitory action of alpha 26-46 was dose dependent, and a significant negative correlation was found between the maximum TSI activity of the serum sample and the inhibition achieved by the synthetic peptide, suggesting that differences in TSI affinity and/or titer may account for the variable inhibitory activity of the peptides. These results suggest that TSI interact with the TSH receptor at the site that recognizes the portion of the TSH alpha-subunit represented by the synthetic peptide alpha 26-46 and, thus, support the concept that the TSH-binding site of the TSH receptor is the site of antigen binding between TSI and the thyroid cell.

The effects of transforming growth factor-beta on growth and differentiation of the continuous rat thyroid follicular cell line, FRTL-5.

Transforming growth factor-beta (TGF beta) has been shown to influence the growth and differentiation of many widely varied cell types in vitro, including some that are endocrinologically active. We have investigated the previously unknown effects of this unique growth factor in the differentiated rat thyroid follicular cell line FRTL-5. The cells demonstrated specific, high affinity binding of TGF beta, and as with other epithelial cells, the growth of these thyroid follicular cells was potently inhibited by addition of TGF beta to the culture medium. TGF beta caused a significant reduction in TSH-sensitive adenylate cyclase activity in the cells. The addition of (Bu)2cAMP along with the growth factor to cultures partially reversed the characteristic morphological changes seen with TGF beta, but did not reverse the growth inhibition. To further investigate the possible mechanisms of the effects of TGF beta on the cells, we measured the influence of the growth factor on [125I]TSH binding. TGF beta did not compete for specific TSH-binding sites; however, exposure of the cells to TGF beta for 12 or more h resulted in a dose-dependent down-regulation of TSH receptors that was fully reversible. While cellular proliferation was potently inhibited by TGF beta, differentiated function, as manifest by iodine-trapping ability, was stimulated by the growth factor. This stimulation of iodine uptake was independent of, and additive to, the stimulatory effects of TSH. Finally, FRTL-5 cells in serum-free medium and in response to TSH were shown to secrete TGF beta-like activity that competed for [125I]TGF beta in a RRA. These studies suggest that TGF beta may represent an autocrine mechanism of controlling the growth response to TSH in thyroid follicular cells, while allowing the continuance of differentiated function.

Clinical utility of thyrotropin-receptor antibody assays: comparison of radioreceptor and bioassay methods.

Thyrotropin (thyroid-stimulating hormone or TSH)-receptor antibodies, important in the pathogenesis of Graves' disease, can be assayed by one of two methods: (1) bioassays that measure stimulation of thyroid cellular activity by patient immunoglobulins or (2) radioreceptor assays that measure inhibition of binding of labeled TSH to TSH receptors by the same substances. In this study, we report our experience with bioassay of thyroid-stimulating immunoglobulins (TSI) based on measurement of generation of cyclic adenosine monophosphate in a clone of the Fisher rat thyroid cell line (FRTL-5) in 279 patients, and we compare, in 163 consecutive samples, the results obtained by a radioreceptor assay for thyrotropin-binding inhibiting immunoglobulins (TBII). Among the untreated, hyperthyroid patients with Graves' disease, TSI were present in 95% (38 of 40), and TBII were present in 85% (17 of 20). In patients with euthyroid Graves' disease, TSI were found in 57% (16 of 28), and TBII were present in 41% (7 of 17). Of 49 nongoitrous and euthyroid controls, only 4% had TSI and 3% had TBII. Extremely high TSI indices were found in all patients who had pretibial dermopathy (N = 10) or severe Graves' ophthalmopathy (N = 19) requiring orbital decompression. We conclude that both assays are highly sensitive and specific in diagnosing Graves' disease. The TSI bioassay was more sensitive (P less than 0.001) than the TBII radioreceptor assay in detection of Graves' disease. In our experience, both assays have proved useful in the diagnosis of euthyroid Graves' disease with ophthalmopathy and atypical manifestations of hyperthyroid Graves' disease.

The effects of synthetic alpha-subunit peptides on thyrotropin interaction with its receptor.

Synthetic peptides of the alpha-subunit of human glycoprotein hormones have been shown previously to inhibit binding of [125I]iodo-hCG to ovarian membranes, thus indicating the importance of the alpha-subunit in the structure-function relationships of the gonadotropic hormone. These same synthetic alpha-subunit peptides, the sequences of which are common to all human glycoprotein hormones, were found to inhibit the binding of [125I]iodo-TSH to human thyroid membrane preparations and FRTL-5 rat thyroid cells. The active portions of the subunit were represented in synthetic peptides alpha 21-35, alpha 31-45, alpha 26-46, and alpha 81-92, indicating that 2 separate sites within the alpha-subunit have binding activity for TSH. Peptides alpha 26-46 and alpha 31-45 were also found to potently inhibit the stimulation of adenylate cyclase activity by bovine TSH in TSH bioassay using FRTL-5 cells. Seven other synthetic peptides, including the remainder of the 92-amino acid sequence of the alpha-subunit, demonstrated little or no ability to inhibit binding of the tracer or inhibit the bioactivity of intact TSH. The findings were very similar to those of previous studies involving hCG binding, except that the two active sites appeared to be somewhat shifted towards the COOH-terminal end of the subunit. These studies support the concept of the importance of the alpha-subunit in receptor binding of all glycoprotein hormones and demonstrate the utility of the overlapping synthetic peptide strategy in investigations of protein structure-function relationships.

Diagnostic evaluation of pheochromocytoma.

Progress in the diagnostic evaluation of pheochromocytoma has taken place in biochemical studies and localization techniques. Measurement of fractionated catecholamines and their metabolites has been subjected to sensitivity and specificity assessment. Magnetic resonance imaging and isotopic imaging have led to much better localization of extra-adrenal tumors. Flow cytometry of the DNA of the tumor cells very likely indicates the malignant nature of the tumor.

Microassay for nuclear binding of steroid receptors with use of intact cells from small samples of avian and human tissue.

A micro version of a nuclear binding assay to assess the biological activity of receptors for steroid hormones was developed for application to small (needle) biopsies of human tumors for the purpose of predicting responses to steroid therapy. This easier assay requires 10-fold less tissue than the original nuclear binding assay described for progesterone receptors in the avian oviduct, endometrium, and endometrial carcinomas (Spelsberg TC, et al., Endocrinology 1987;121:631). We describe the application of this micro assay to normal avian oviduct and cancers of the human breast, and we demonstrate a tissue specificity and saturation of nuclear binding. The micro assay reliably measured as little as 0.5 mg equivalents of tissue per assay tube. Results for breast tumors determined to be estrogen-receptor-positive by the standard dextran-coated charcoal method were also determined with this nuclear binding assay. As described previously for progesterone receptors in endometrial carcinomas, some receptor-positive breast biopsies displayed negligible capacity for nuclear binding. Therefore, with the present assay we have identified nonfunctional receptors in these biopsies, which may be useful for accurate prediction of patients' responses to therapy with hormones.

Somatic and autonomic function in progressive autonomic failure and multiple system atrophy.

We studied 62 consecutive patients with progressive autonomic failure (PAF) or multiple system atrophy (MSA) (26 PAF; 36 MSA). Patients were well matched in age (67 vs 66 years), duration (39 vs 36 months), and severity of autonomic failure (median values for PAF and MSA). Peripheral somatic neuropathy occurred in 2 patients with PAF and 7 patients with MSA. Postganglionic sudomotor and vasomotor functions were studied using the quantitative sudomotor axon reflex test and supine plasma norepinephrine. The extent and severity of autonomic failure were assessed by the thermoregulatory sweat test, by heart rate responses to deep breathing and the Valsalva maneuver, and by blood pressure recordings. Severe and widespread anhidrosis was found in both PAF and MSA patients. Postganglionic sudomotor failure occurred at the forearm in 50% each of PAF and MSA patients and at the foot in 69% and 66% of PAF and MSA patients, respectively. However, postganglionic sudomotor function was preserved in some patients with anhidrosis on thermoregulatory sweat test, indicating a preganglionic lesion. Vagal abnormalities were found in 77% and 81% of PAF and MSA patients. Supine plasma free norepinephrine values were significantly reduced in PAF (p less than 0.001), but not in MSA, patients. Standing plasma norepinephrine values were reduced in both PAF (p less than 0.001) and MSA (p less than 0.001) patients. We conclude the following: (1) PAF is characterized by combined postganglionic sudomotor and adrenergic failure. (2) MSA is associated with a similar frequency of postganglionic sudomotor failure, but postganglionic adrenergic denervation was uncommon. (3) Preganglionic neuron is also involved in both disorders, but more severely in MSA. (4) Somatic neuropathy may occur.

Transforming growth factor type beta in normal human urine.

TGF beta has been identified in normal human urine specimens from five individuals studied for five consecutive days. The peptide was extracted from urine using Sepralyte C1 beads. Detectable levels of [125I]TGF beta competing activity as measured by radioreceptor assay was found in about half of the specimens studied. The protein isolated from urine using C1 Sepralyte beads was further purified using Biogel P-60 column chromatography. Fractions were tested for TGF beta and EGF competing activity using radioreceptor assays. TGF beta and EGF extracted from urine are clearly separated by column chromatography. Two distinct EGF peaks and a single TGF beta peak were observed. Fractions having [125I]TGF beta competing activity were pooled and further purified using reverse-phase HPLC. HPLC fractions having [125I]TGF beta competing activity were tested for bioactivity using a soft agar assay. The fractions were capable of stimulating soft agar growth of AKR-2B (clone 84A) cells and cross reacted with a TGF beta antibody in a radioimmunoassay. The presence of TGF beta in normal human urine was also demonstrated by immunoblotting. These results also suggest that C1 bead extraction of urine specimens can be used as a rapid first step in purification of TGF beta.