Pheochromocytoma and the normal adrenal medulla: improved visualization with I-123 MIBG scintigraphy

The radiopharmaceutical iodine 131 metaiodobenzylguanidine (I-131 MIBG) has been shown to locate pheochromocytomas scintigraphically with a false-negative rate of approximately 13%. To improve image quality and reduce the false-negative rate, I-123 was examined as a radioactive label for MIBG, as it has many advantages over I-131, including superior dosimetry and better detection efficiency. Diagnostic doses of 0.5 mCi (18.5 MBq) I-131 MIBG and 10.0 mCi (370.0 MBq) I-123 MIBG with nearly equivalent radiation dosimetries were compared in 18 patients with known or suspected pheochromocytomas. Images of superior quality were obtained with I-123 MIBG in 18 of 18 patients, and in eight cases lesions not visualized on I-131 MIBG scintigraphy were portrayed. A further advantage of I-123 MIBG is that it permits single photon emission computed tomography (SPECT). This was performed in six cases and provided additional information in three cases. The adrenal medullae were definitely visualized using I-123 scintigraphy in eight of 14 patients still possessing adrenal glands, whereas I-131 MIBG images portrayed the adrenal medulla in only one of 14 cases. Five remaining patients had multiple abdominal tumor deposits that were difficult to differentiate from normal adrenal medullae.     

The influence of bromocriptine and transsphenoidal surgery on urinary androgen metabolite excretion in acromegaly

The urinary excretion of the androgen metabolites aetiocholanolone (E) and androsterone (A) as well as DHEA, 11-hydroxy-androsterone and the cortisol metabolites 11-oxo-aetiocholanolone and 11-hydroxyaetiocholanolone in normoprolactinaemic and hyperprolactinaemic male and female acromegalics was studied and compared with that of appropriate control groups. In addition several plasma hormones were also measured. The growth hormone level in the patient group varied from 10-550 mU/l. The excretion of both 11-hydroxy-androsterone and DHEA was normal. The excretion of androsterone had decreased, while aetiocholanolone and cortisol metabolite excretion had increased. The ratio between aetiocholanolone and androsterone (E/A) excretion was significantly increased in all patient groups, but no correlation was found between the growth hormone level and the E/A ratio. Treatment with bromocriptine caused a decrease in the E/A ratio in patients with decreased growth hormone levels, but not in patients in whom the growth hormone level remained unchanged. After selective transsphenoidal removal of the pituitary adenoma the E/A ratio decreased significantly. The increased E/A ratio in untreated patients could not be attributed to eventual changes in plasma levels of cortisol, thyroxine, prolactin, testosterone or oestrogens. We therefore suggest that growth hormone is involved in androgen metabolism in acromegaly.     

Absorption rate and bioavailability of valproic acid and its sodium salt from rectal dosage forms

Summary Rectal and oral absorption of valproic acid and its sodium salt by man were compared to explore the possibility of rectal administration of the drug. The plasma concentration of valproic acid was measured by gas chromatography after a single oral dose of sodium valproate 600 mg, and after single rectal doses of sodium valproate 600 mg and valproic acid 520 mg, in a cross-over study in 7 volunteers. The rectal dosage forms included fatty suppositories and aqueous solutions. Compared with oral administration, rectal absorption of sodium valproate from an aqueous micro-enema was fast and complete. The free acid was absorbed more rapidly from fatty suppositories than was the sodium salt. The absorption rate from the rectum increased with the dose of valproic acid. Both findings are consistent with a diffusion — absorption mechanism based on the pH-partition hypothesis. Differences in the chemical composition of the fatty suppository base were not reflected in differences in absorption rate and relative bioavailability. No essential difference in absorption rate was observed if volunteers remained lying or sitting during the experiment. Rectal dosing with valproic acid 520 mg dissolved in 4 ml suppositories, twice a day resulted in steady-state plasma concentrations of 50 to 100 µg · ml^–1, within the therapeutic range.Data have been presented in: F. Moolenaar, Ph. D. Thesis, Groningen, The Netherlands     

Knowledge, attitudes, and practices related to mold exposure among residents and remediation workers in posthurricane New Orleans

To assess knowledge, attitudes, and practices related to mold exposure in postflood New Orleans, the authors surveyed 159 residents and 76 remediation workers, using logistic regression to explore associations. Nearly all answered "yes" to the questionnaire item, "Do you think mold can make people sick?" and most knew respirators were recommended for cleaning mold. Residents (87%) and workers (47%) said they believed that television or radio were the best ways to communicate information about mold. Workers (24%) also suggested employers provided the best means for communication of this information. Few participants reliably used all recommended protective equipment. Residents cited respirator discomfort and unavailability as reasons for noncompliance; workers cited discomfort and inadequate training, with 50% reporting respirator fit testing. Spanish-speaking workers relied on employers for information. Self-employed workers used protective equipment infrequently. The authors recommend that information on postflood mold exposure be disseminated through media and employers, that protective equipment be made readily available for residents, and that workers receive better training and fit testing. In addition, they suggest that targeted approaches may benefit Spanish-speaking workers and the self-employed.     

Splenectomy in myeloid metaplasia

Between 1960 and 1977, 50 patients with agnogenic myeloid metaplasia were splenectomized. Twenty-five of 26 patients with painful splenomegaly, 4 of 9 patients with refractory hemolytic anemia, 4 of 10 patients with refractory thrombocytopenia, and 4 of 4 patients with portal hypertension showed significant benefit from the procedure. There were five immediate postoperative deaths. Four of these deaths occurred early in our series of splectomies for myeloid metaplasia before 1970. Only one death has occurred in the last 21 patients operated on. Survival following splenectomy averaged 25.5 mo.     

Interaction between digoxin and nifedipine at steady state in patients with atrial fibrillation

The possible kinetic and hemodynamic interactions between digoxin and nifedipine were evaluated in nine patients with atrial fibrillation who were receiving chronic digoxin. After 2 control weeks, nifedipine (20 mg b.i.d.), in a new formulation with sustained release characteristics, was added to the therapeutic regimen for 2 weeks. Trough serum digoxin concentrations and peak nifedipine concentrations were determined repeatedly. On the same days, resting blood pressure and heart rate were measured. During nifedipine administration, serum digoxin levels increased by 15% from 0.87 +/- 0.38 to 1.04 +/- 0.37 ng/ml (mean +/- SD, p less than 0.05). This was accompanied by a reduction in systolic and diastolic blood pressure of 16 +/- 6 (p less than 0.01) and 12 +/- 5 mm Hg (p less than 0.001), respectively. In two patients, noncardiac side effects were reported. In two other patients, nifedipine was discontinued because of skin rash and severe headache, respectively. In conclusion, plasma digoxin levels were elevated slightly in the presence of nifedipine, but this probably has little clinical relevance.