Consecutive infrared multiphoton dissociations in a fourier transform ion cyclotron resonance mass spectrometer.

Consecutive infrared multiphoton dissociations (IRMPD) may be observed in a Fourier transform ion cyclotron resonance mass spectrometer (FTICR). This is the IRMPD equivalent of previous MS(n)() experiments using CID. This work presents a versatile technique, using a bistable shutter to gate ON and OFF a continuous-wave (CW) CO(2) laser for multiple irradiation periods of 0.1-1000 s duration. Consecutive photodissociations, up to MS(4), are demonstrated for the proton-bound dimer of diethyl ether and the resulting fragment ions. The photoproducts are formed close to the center of the FTICR cell, resulting in high product ion recovery efficiency. This differs from CID products, which are formed throughout the FTICR cell causing reisolation/detection problems. The fragmentation resulting from the use of low-intensity, CW, infrared laser radiation is shown to be much more energy selective than CID. Photodissociation of C(2)H(5)OH(2)(+) ion produces the lowest energy product ion exclusively, even though the two product channels differ only by ∼5 kcal/mol. Low-energy CID, however, produces a mixture of C(2)H(5)(+) and H(3)O(+) products in the ratio of 1.3:1. Hence, the higher energy pathway (C(2)H(5)(+)) is substantially favored. The current results indicate that this IRMPD MS(n)() technique may be successfully applied to large biomolecules prepared by electrospray or MALDI.

Contemporary therapy of prolactin-secreting adenomas.

Prolactin-secreting pituitary tumors are common benign pituitary neoplasm that cause amenorrhea, galactorrhea, and infertility. Inhibition of prolactin secretion by a dopamine agonist restores menses and reduces tumor size. This article outlines an approach to therapy and discusses the use of estrogen in women with prolactinomas.

Septo-optic dysplasia associated with polyendocrine dysfunction.

Septo-optic dysplasia (SOD) is a rare congenital disease that has been described in association with hypothalamic dysfunction. A case of polyendocrine dysfunction is described in a 22 year-old white female with septo-optic dysplasia. Findings included atrophic optic nerves, a cavum septum pellucidum and a small pituitary gland detected by magnetic resonance imaging. The patient had central diabetes insipidus, Hashimoto's thyroiditis, and gestational diabetes mellitus. A review of the literature is presented. A careful and detailed endocrine evaluation is needed in patients with SOD.

Neurologic complications of thyroid and parathyroid disease.

Common thyroid and parathyroid disorders present with reversible neurologic signs and symptoms affecting the central and peripheral nervous system, musculature, and mental function. Patients with thyrotoxicosis may have myopathy, spasticity, seizures, and multiple psychiatric symptoms. A deficiency of thyroid hormone also causes muscle weakness and may be accompanied by reversible muscle hypertrophy or movement disorders. The chronic hypercalcemia that develops secondary to hyperparathyroidism produces many psychiatric and cognitive symptoms, as well as a reversible myopathy. Calcium deficiency leads to neuromuscular irritability, paresthesias, and tetany. Psychiatric disorders are also common in this disorder.

Intracranial dissemination of an ACTH secreting pituitary neoplasm--a case report and review of the literature.

A 52-year-old woman developed recurrent hypercortisolism 3 yr after successful surgical treatment of Cushing's disease. At postmortem, eosinophilic pituitary tissue showing positive ACTH immunohistochemical staining was present in the frontal lobe and cerebellum but there was no tumor in the sella. In the absence of a pituitary tumor, extrasellar ACTH producing tissue could arise from seeding of the cerebrospinal fluid with tumor cells at the time of operation or from an atypical pituitary carcinoma. In this report we review the mechanisms of intracranial dissemination of pituitary tissue and ACTH-secreting pituitary carcinomas, including parasellar invasion, meningeal seeding, and cerebrospinal and hematogenous spread.