Neuronal and Glial Glutamate Transporters Possess an SH-based Redox Regulatory Mechanism

Glutamate uptake into nerve cells and astrocytes via high-affinity transporters controls the extracellular glutamate concentration in the brain, with major implications for physiological excitatory neurotransmission and the prevention of excitotoxicity. We report here that three recently cloned rat glutamate transporter subtypes, viz. EAAC1 (neuronal), GLT1 and GLAST (glial), possess a redox-sensing property, undergoing opposite functional changes in response to oxidation or reduction of reactive sulphydryls present in their structure. In particular, thiol oxidation with 5,5'-dithio-bis(2–nitrobenzoic) acid (DTNB) and disulphide reduction with dithiothreitol (DTT) result, respectively, in reduced and increased uptake capacity by a preparation of partially purified brain transporters as well as by the three recombinant proteins reconstituted into liposomes. In this model system, EAAC1, GLT1 and GLAST react similarly to DTT/DTNB exposures despite their different contents of cysteines, suggesting that only the conserved residues might be involved in redox modulation. Redox sensitivity is a property of the glutamate transporters also when present in their native cell environment. Thus, by using cultured cortical astrocytes and the whole-cell patch-clamp technique we were able to observe dynamic increase and decrease of the glutamate uptake current in response to application of DTT and DTNB in sequence. Moreover, in the same paradigm, DDT-reversible current inhibition was observed with hydrogen peroxide instead of DTNB, indicating that the SH-based redox modulatory site is targeted by endogenous oxidants and might constitute an important physiological or pathophysiological regulatory mechanism of glutamate uptake in vivo     

Treatment of post-menopausal osteoporosis with recombinant human growth hormone and salmon calcitonin: a placebo controlled study

OBJECTIVE The usefulness of GH in the treatment of post-menopausal osteoporosis (PMO) is still debated. We have studied the effects of recombinant human GH (rhGH) given alone or in combination with salmon calcitonin (sCT) in the treatment of PMO. PATIENTS Thirty women with established PMO (aged 61.1±4.4 years) were divided into 3 groups of 10 and randomly assigned to 3 treatment sequences: rhGH (12 IU/day) s.c. for 7 days, followed by sCT (50 IU/day) s.c. for 21 days and by 61 days without treatment (group 1); placebo for 7 days, followed by sCT for 21 days and by 61 days without treatment (group 2); rhGH for 7 days, followed by placebo for 21 days, and by 61 days without treatment (group 3). Each cycle was repeated 8 times (24 months). MEASUREMENTS At days 0, 8, 29 and 90 of each cycle, serum IGF-I, calcium, phosphate, osteocalcin, alkaline phosphatase and urinary excretion of calcium, hydroxyproline and pyridinoline cross-links (Pyr) were measured. At months 0, 6, 12, 18 and 24, bone mineral density (BMD) was measured by dual-photon absorptiometry (DPA), at lumbar spine (LS), femoral shaft (F) and distal radius (DR). RESULTS A significant increase in serum osteocalcin and urinary calcium, hydroxyproline and Pyr was detected after each rhGH period. In group 1, BMD at lumbar spine increased by 2.5% at year 2; in contrast, significant (P<0.05) decreases in BMD-LS values were found in patients treated with CT and placebo (group 2) and with GH and placebo (group 3). BMD-F did not show any significant change in patients of group 2, but a significant (P<0.05) decrease was found in groups 1 and 3. BMD-DR did not show any significant change with respect to baseline in any of the three groups. No significant difference between the three groups was found in bone mass at the three different regions. CONCLUSIONS Our study demonstrates that treatment with rhGH increases bone turnover in post-menopausal osteoporotic women. Combined treatment with rhGH and CT over a period of 24 months is able to maintain bone mass at lumbar spine and distal radius, but induces a decline at femoral shaft; therefore, it does not seem particularly useful in the therapy of post-menopausal osteoporosis.     

Acquired Brown's syndrome caused by frontal sinus osteoma

A 32-year-old man had a history of acquired Brown's syndrome associated with diplopia, proptosis, downward displacement of the globe, and lid edema. A CT scan of the orbit revealed an osteoma arising from the left frontal sinus and extending into the left orbit. After surgical extirpation the proptosis and diplopia disappeared and the globe returned to normal. To our knowledge, such a case has not been reported previously.     

Growth hormone treatment affects plasma LH pulsatile release in women with secondary amenorrhoea

OBJECTIVE Since growth hormone (GH) is administered as a co-gonadotrophic factor in ovulation induction, this study aimed to assess the action of GH on the episodic pulsatile release of LH and FSH in amenorrhoeic patients. PATIENTS AND DESIGN Nineteen patients affected by hypothalamic amenorrhoea were enrolled for this study: group A, 9 patients with normal gonadotrophins; group B, 10 patients with low gonadotrophins. Both groups were studied during GH infusion (0015 IU/min for 4 hours) and after 7 days of GH administration (0 1 IU/kg/day). Patients underwent a 4-hour pulsatility study, with blood sampling every 10 minutes. A standard GnRH test (10 μ g i.v. bolus) was performed immediately after the pulsatility evaluation. MEASUREMENTS LH and FSH were assayed with an IFMA method; oestradiol and IGF-I were assayed by RIA and IRMA, respectively. PULSE DETECTION Time series were analysed with Detect program. RESULTS All patients showed similar LH and FSH pulsatile characteristics both under baseline conditions and during GH infusion. After 7 days of GH administration, episodic FSH release showed no change in either group. On the contrary, LH pulse frequency (mean ± SE) significantly increased in group A (4 0±0 2 peaks/4h, P&kt;0 05), while putse amplitude (baseline, 3.9± 0 6 IU/I; after 7 days, 2.9±0.3 IU/I, P<0 05), and integrated LH plasma concentrations (baseline, 7.6 ±1–1 IU/I; after 7 days, 5±0 8 IU/I, P<0 05) were significantly decreased. No significant changes were observed for LH pulse frequency, amplitude or integrated LH plasma concentrations in hypogonado-trophinaemic patients (group B). Plasma oestradiol levels were significantly increased only in group A (baseline, 154 18±23 8 pmoI/I; after 7 days, 380 3±110 1 pmoI/I, P < 005), while IGF-I levels were significantly increased in both groups after 7 days of GH administration (P<0 05). No significant differences were observed in the gonadotropin responses to GnRH test before and after GH administration. CONCLUSIONS The present study showed that the administration of GH in amenorrhoeic patients determines the significant changes in episodic LH release in those subjects with normal LH plasma levels and suggests that the action of GH may be dependent upon the ovarian-pituitary feedback action.     

Focal Adhesion Kinase in Rat Central Nervous System

Focal adhesion kinase (pp125^FAK, FAK) is a 125 kDa non-receptor tyrosine kinase enriched in focal adhesions of various cell types, where it is thought to transduce signals triggered by contact with the extracellular matrix. We have studied the expression and localization of FAK in rat CNS. Immunoblotting, immunohistochemistry and in situ hybridization revealed the presence of FAK in all regions of the adult brain and demonstrated its enrichment in specific neuronal populations of the cerebral and cerebellar cortex, as well as in the hippocampus. During development, FAK protein levels were highest around birth in cerebral cortex and caudate putamen and decreased in the adult. In situ hybridization revealed enrichment of FAK mRNA in the ventricular germinative and external layers during the last period of embryonic growth. In primary cultures FAK immunoreactivity was localized in focal adhesions in astrocytes, whereas in developing neurons the highest levels were found in growth cones and perikarya. In the growth cone, FAK immunoreactivity colocalized with actin filaments. In mature neurons FAK appeared to be distributed in the whole cytoplasm, with no enrichment in any cellular compartment. Our results demonstrate the presence of high levels of FAK in rat CNS, maximal during development but persistent in the adult. Its enrichment in growth cones suggests that it may play a role in neurite outgrowth, as well as in plasticity in the adult.     

Fish consumption (hair mercury) and nutritional status of Amazonian Amer-Indian children.

Fish are abundant and important dietary items for the Amer‐Indians, and total hair‐Hg (HHg) concentration is a reliable marker of fish consumption. We studied the impact of fish consumption (HHg) on the nutritional status of Indian children of Eastern Amazonia. Weight‐for‐height Z score (WHZ) was measured, and HHg was determined in 203 children younger than 10 years of age in three villages. There was significantly higher fish consumption in Kayabi children (16.55 μg Hg/g; SD, 11.44) than in children of the Munduruku villages of Missão‐Cururu (4.76 μg Hg/g; SD, 2.09) and Kaburua (2.87 μg Hg/g; SD, 2.13). Anthropometric indices showed WHZ means of ?0.27, ?0.22, and 0.40, respectively, for Kayabi, Missão‐Cururu and Kaburua villages. Despite a different pattern of fish‐protein consumption between tribes, there was no significant correlation between WHZ and HHg concentrations (r² = 0.0079; P < 0.2021). Dietary differences among Amazonian tribes can be traced and used in measuring health outcomes. Higher fish consumption, although important for Kayabis, was compensated by other protein sources by the Kaburua villagers. Am. J. Hum. Biol. 17:507–514, 2005.© 2005 Wiley‐Liss, Inc.     

Indices of mercury contamination during breast feeding in the Amazon Basin

Mercury pollution, due to gold mining has spread through the Amazon ecosystem reaching the food chain and affecting the indigenous people of the region. We studied the mercury contamination of 47 mothers and infants and the role of breast feeding in indices of mercury body burden in both groups, by measuring hair and milk Hg levels. Total mercury concentration of breast milk ranged from 0.0 to 24.8 (5.85, 5.2 S.D.) ng/g. Calculated levels of mercury exposure of breast fed babies indicated that 53% were above tolerable daily intakes (0.5 μg/kg body weight) recommended for adults by WHO. Mercury concentration in maternal hair was higher than in hair from breast-fed babies. Correlation analysis showed that mercury hair concentration in infants was significantly affected by maternal mercury contamination during pregnancy, but not during the post-natal breast-feeding period. The mercury concentration in milk was not significantly correlated with maternal or infant's hair Hg. A statistically significant correlation was found only between maternal and infant's hair mercury concentration (r=0.675; P=0.0001).     

Multidisciplinary approach to "accidental" falls in the elderly: A case report

Falls in the elderly are commonly and often wrongly identified as "accidental". We report a case of an elderly woman admitted to first aid for a trauma due to an accidental fall. Geriatric multidisciplinary evaluation revealed mild cognitive impairment associated with depressive symptoms; both findings made the anamnesis uncertain. Syncope algorithm was applied and "tachy-brady form of sick sinus syndrome" was diagnosed. Differential diagnosis between "accidental" and "apparently accidental" falls in elderly patients is very difficult but a multidisciplinary geriatric evaluation can clarify the correct diagnosis.     

Her-2/neu evaluation in Sister Mary Joseph's nodule from breast carcinoma: a case report and review of the literature

Sister Mary Joseph's nodule (SMJN) involving the umbilicus can often be a clinical sign of metastatic cancer, but rarely cancer originating from the breast. We report a rare case of umbilical metastases from breast cancer and reviewed the literature. A 54-year-old woman was referred to a pre-surgery clinic for an examination of an umbilical nodule. The patient had a history of ductal breast carcinoma. Cytological smear from fine needle aspiration showed epithelial neoplastic cells resembling those of breast carcinoma. Neoplastic cells from tissue were positive for cytokeratin 8–18, estrogen and progesterone receptor and negative for E-cadherin and had a low proliferative index. Her-2/neu immunodetection showed a 2+ equivocal positive rate, but Her-2/neu gene amplification was found on the cytological smear by fluorescence in situ hybridization analysis. Similar results were obtained within a tissue section. Concordant findings have been obtained when comparing the recent American Society of Clinical Oncology/College of American Pathologists scoring system. Fine needle aspiration from the SMJN is a useful tool for the diagnosis of metastatic breast cancer. Furthermore, the predictive biomarkers for tumors of the breast, hormonal receptors and Her-2/neu not only assist with the identification of the source of the metastatic disease but also provide clinical information for patient management.