Genetic disorders of iron metabolism and chronic inflammation often evoke local iron accumulation. In Friedreich ataxia, decreased iron-sulphur cluster and heme formation leads to mitochondrial iron accumulation and ensuing oxidative damage that primarily affects sensory neurons, the myocardium, and endocrine glands. We assessed the possibility of reducing brain iron accumulation in Friedreich ataxia patients with a membranepermeant chelator capable of shuttling chelated iron from cells to transferrin, using regimens suitable for patients with no systemic iron overload. Brain magnetic resonance imaging (MRI) of Friedreich ataxia patients compared with agematched controls revealed smaller and irregularly shaped dentate nuclei with significantly (P < .027) higher H-relaxation rates R2*, indicating regional iron accumulation. A 6-month treatment with 20 to 30 mg/kg/d deferiprone of 9 adolescent patients with no overt cardiomyopathy reduced R2* from 18.3 s ؊1 (؎ 1.6 s ؊1 ) to 15.7 s ؊1 (؎ 0.7 s ؊1 ; P < .002), specifically in dentate nuclei and proportionally to the initial R2* (r ؍ 0.90). Chelator treatment caused no apparent hematologic or neurologic side effects while reducing neu- IntroductionTissue iron overload and ensuing organ damage have generally been identified with transfusional hemosiderosis and genetic hemochromatosis. 1 Liver, heart, and endocrine glands are among the most affected organs in these forms of systemic iron overload. 1 The source of tissue iron overload has been traced to plasma iron originating from enteric hyperabsorption of the metal and/or enhanced red cell destruction. The labile forms of plasma iron (LPI) that appear as transferrin become saturated, permeate into particular cell types by unregulated mechanisms, and cause labile iron pools to raise and challenge cellular antioxidant capacities. 2 However, in chronic inflammation 3 and in various genetic disorders, 4 iron accumulates in particular cell types attaining toxic levels, even in the absence of circulating LPI and often even in iron-deficient plasma. In Friedreich ataxia (FA), an expansion of a GAA repeat in the first intron of the nuclear encoded frataxin gene 5,6 results in underexpression of a mitochondrial protein involved in the assembly of iron-sulphur cluster proteins (ISPs) and/or in protecting mitochondria from iron-mediated oxidative damage. 7 The defective ISP formation that causes a combined aconitase and respiratory chain deficiency (complex I-III) leads in turn to mitochondrial accumulation of labile iron 8,9 and ensuing oxidative damage in brain, heart, and endocrine glands. However, the pathophysiologic role of mitochondrial iron accumulation in oxidative damage found in FA 5,9 and other neurologic disorders [10][11][12][13] has not been resolved.In analogy to transfusional iron overload, histopathologic and magnetic resonance imaging (MRI) studies of FA patients have shown that iron accumulates not only in the heart but also in the spinocerebellar tracts (dentate nuclei) and spinal cord. 10 Those and othe...
We studied the incidence of late-onset adrenal hyperplasia as a cause of hirsutism, its association with the major histocompatibility complex, and its clinical expression. Twenty-four of 400 women seen because of hirsutism were found to have late-onset adrenal hyperplasia, diagnosed on the basis of a high plasma level of 17-hydroxyprogesterone, and its marked increase after ACTH stimulation. The degree of hirsutism varied widely. Plasma antigen levels were high, especially the level of androstenedione, whereas 5 alpha-reductase activity, considered to be a good index of peripheral androgen utilization, showed frequent normal or low values. The 24 patients were genotyped, along with 84 family members, and plasma hormones were measured in the family members. We found a high correlation between late-onset adrenal hyperplasia and HLA antigens B14 and Aw33. Similar biologic profiles were observed in the patients and those of their siblings who were HLA identical (n = 9), confirming that late-onset adrenal hyperplasia is linked to the histocompatibility complex. These nine siblings had no hirsutism. We therefore conclude that the role of skin sensitivity to androgens is important in determining the clinical expression of this disorder.
To determine whether the route of administration or the type of estrogen used in estrogen replacement therapy (ERT) is more important in avoiding effects on hepatic function, 24 postmenopausal women were studied before and at the end of 2 months of oral or percutaneous administration of the same estrogen, estradiol-17 beta (E2). The treatments studied were oral micronized E2, 2 mg/day (9 women); oral E2 valerate, 2 mg/day (5 women), and percutaneous E2, 3 mg/day (10 women). Specific plasma biological and biochemical markers of estrogenic action were evaluated, namely, E2, estrone (E1), LH, FSH, sex steroid binding protein (SBP), renin substrate, antithrombin activity, and lipoproteins (high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein triglycerides). Both oral and percutaneous administration of E2 increased plasma E2 levels up to midfollicular values and decreased LH and FSH levels into the same range. Oral administration of E2 led to substantial increases in plasma E1, SBP, renin substrate, and VLDL levels, whereas AT decreased significantly. Percutaneous administration of E2 led to a physiological plasma E1/E2 ratio and did not induce any change in hepatic proteins. These data suggest that the route of administration of E2 determines the biochemical response to ERT in postmenopausal women. SBP is the most sensitive marker of the liver action of estrogen, and triglycerides also are simple and useful markers for this effect. Percutaneous E2 therapy is an effective method of ERT, and has no measurable effects on hepatic markers of estrogen action.
In this population-based prospective cohort study, ever users of LNG-IUS had a strongly reduced risk of ovarian and endometrial cancer compared to never users, with no increased risk of breast cancer.
Continuous monitoring of the electrophysiological manifestations of GnRH pulse generator activity was achieved by radiotelemetry throughout the menstrual cycles of unrestrained rhesus monkeys. The characteristic increases in hypothalamic multiunit activity (MUA volleys) associated with each LH pulse measured in the peripheral circulation were of lower frequency during the luteal phase than in the follicular phase of the cycle. Multiunit activity volley frequency increased as functional luteolysis progressed and achieved maxima of approximately one volley per hour within the first few days of the follicular phase. Unexpectedly, a dramatic decline in pulse generator frequency was observed coincidentally with the initiation of the preovulatory LH surge. Evidence is presented to support the conclusion that this deceleration of pulse generator activity is the consequence of the preovulatory rise in plasma estrogen concentration. As reported in women, a significant reduction in GnRH pulse generator frequency was observed at night during the follicular phase, but not during the luteal phase, of the menstrual cycle.
The effect of corticotropin-releasing factor (CRF) on the hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator, the central neuronal system governing pulsatile pituitary luteinizing hormone (LH) secretion, was studied electrophysiologically in 6 ovariectomized rhesus monkeys bearing bilateral arrays of recording elecrodes implanted in the mediobasal hypothalamus. ‘Volleys’ of increased multiunit activity (MUA) were recorded for 6–10 h in animals placed in primate chairs. The circulating concentrations of LH and cortisol were determined by radioimmunoassay in blood samples taken every 10 min for 3–4 h prior to the administration of CRF (200 µg, i.v.) and for 3–6 h thereafter. CRF resulted in a significant decrease in the frequency of pulse generator activity in 4 of 6 animals, a significant decrease in the duration of MUA volleys and a rise in circulating cortisol levels in all 6 monkeys. Treatment with metyrapone (30 mg/kg, i.m.), an inhibitor of adrenal steroidogenesis that prevented the CRF-induced rise in serum cortisol levels, did not reverse the inhibitory effects of CRF on the frequency or duration of MUA volleys. The opiate antagonist naloxone (0.8 mg/kg, i.v., 10 min prior to CRF followed by 0.8 mg/kg/h infusion) blocked the effects of CRF on MUA volley frequency in 2 of 3 animals, but failed to block the effect of CRF on MUA volley duration, suggesting that endogenous opioids may mediate the action of CRF on pulse generator frequency but not on duration.
Context: Congenital hyperinsulinism (HI) is a common cause of hypoglycemia in infancy. The medical treatment of diazoxide-unresponsive HI is based on a somatostatin analogue. Objective: This study aims at replacing three daily s.c. octreotide (Sandostatin, Novartis) injections by a single and monthly i.m. injection of long-acting release (LAR) octreotide (Sandostatin LP, Novartis) in HI patients. Subjects and method: LAR octreotide was injected every 4 weeks during 6 months and s.c. octreotide injections were stopped after the third injection of LAR octreotide. After this 6-month study, LAR octreotide was continued, with an average follow-up of 17 months. Ten HI pediatric patients unresponsive to diazoxide and currently treated with s.c. octreotide were included in the trial. Glycemias and other parameters (HbA1c, IGF1, height, weight, quality of life (QoL), and satisfaction) were monitored at each monthly visit. Results: For all ten patients, glycemias were maintained in the usual range, HbAlc (mean 5.5%; 95% CI: 4.6-6.2) and IGF1 (mean 89.7 ng/ml; 95% CI: 26-153) were unchanged. Patients gained height significantly (mean 2.7 cm; 95% CI: 1.9-3.4) and no side effect was noted during the study and the later follow-up. Plasma octreotide levels were stable under LAR octreotide. Parents' questionnaires of general satisfaction were highly positive whereas children's QoL evaluation remained unchanged. Conclusion: In these diazoxide-unresponsive HI patients, LAR octreotide was efficient, well tolerated and contributed to a clear simplification of the medical care.
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