Dopamine depresses polysynaptic inhibition in rat subicular neurons

Schizophrenia is considered to be associated with a hyperfunction of the dopaminergic system and with abnormalities in hippocampal information processing. To clarify whether an enhanced dopaminergic activity alters the hippocampal output, the effect of dopamine (DA) on inhibitory postsynaptic responses (IPSPs) in subicular neurons was examined. DA (200 microM) induced a small and inconsistent hyperpolarization that was accompanied by a reduction of membrane resistance. DA decreased polysynaptic IPSPs which was paralleled by a depression of isolated AMPA/kainate and NMDA receptor-mediated excitatory postsynaptic responses (EPSPs). In contrast, DA had no effect on isolated monosynaptic GABA(A) and GABA(B) receptor-mediated IPSP/Cs. We conclude that in addition to membrane effects, DA decreases polysynaptic IPSPs by attenuating the glutamatergic drive onto subicular interneurons.     

Intermittent atrial level right-to-left shunt with temporary hypoxemia in a patient during support with a left ventricular assist device

We report a 56-year-old male patient developing hypoxemia after surgical replacement of infected valves of a left ventricular assist device (LVAD, Novacor) which had supported him during the previous 15 months. Contrast transesophageal echocardiography (TEE) revealed an atrial septal defect with intermittent right-to-left shunt across a patent foramen ovale. We postulate that the shunt detected in this patient occurred as a consequence of reduced pulmonary vascular compliance due to positive end-expiratory pressure (PEEP) and an increase of mean intrathoracic pressure. Furthermore, we hypothesize that synchronized LVAD operation exacerbates any potential right-to-left shunt due to the profound left ventricular unloading which occurs during LVAD support. In this first report of a right-to-left shunt from a previously unrecognized patent foramen ovale in a Novacor patient, the subsequent transient hypoxemia could be managed by avoiding PEEP of more than 3 mmHg, and mean airway pressure of more than 11 mmHg and by careful volume replacement in order to prevent the pump from completely emptying the left ventricle (LV) and the left atrium (LA). Thus, prior to every LVAD implantation a transesophageal contrast echocardiography with Valsalva maneuver should be performed to identify intracardiac right-to-left shunt.     

Switch from a BIVAD to a LVAD in a boy with Kawasaki disease

A 9-year-old boy with Kawasaki disease survived after two severe myocardial infarctions. Thereafter pharmacologically untreatable ventricular arrhythmia and rapidly deteriorating heart failure developed in the patient. After 19 days of biventricular and a further 27 days of left univentricular mechanical circulatory support with the Berlin Heart (Cardiotechnica, Berlin, Germany) assist device the boy successfully underwent heart transplantation. At a follow-up of 54 months, the boy is leading an active and unrestricted life.     

Safety and efficacy of weight training in recent breast cancer survivors to alter body composition, insulin, and insulin-like growth factor axis proteins.

BACKGROUND: This randomized controlled trial assessed the safety and effects of twice-weekly weight training among recent breast cancer survivors. Outcomes included body size and biomarkers hypothesized to link exercise and breast cancer risk. METHODS: A convenience sample of 85 recent survivors was randomized into immediate and delayed treatment groups. The immediate group trained from months 0 to 12; the delayed treatment group served as a no exercise parallel comparison group from months 0 to 6 and trained from months 7 to 12. Measures at baseline, 6 and 12 months included body weight, height, body fat, lean mass, body fat %, and waist circumference, as well as fasting glucose, insulin, insulin resistance, insulin-like growth factor-I (IGF-I), IGF-II, and IGF-binding protein-1, IGFBP-2, and IGFBP-3. Injury reporting was standardized. RESULTS: The intervention resulted in significant increases in lean mass (0.88 versus 0.02 kg, P < 0.01), as well as significant decreases in body fat % (-1.15% versus 0.23%, P = 0.03) and IGF-II (-6.23 versus 28.28 ng/mL, P = 0.02) comparing immediate with delayed treatment from baseline to 6 months. Within-person changes experienced by delayed treatment group participants during training versus no training were similar. Only one participant experienced a study related injury that prevented continued participation. CONCLUSION: Twice-weekly weight training is a safe exercise program for recent breast cancer survivors that may result in increased muscle mass, as well as decreased body fat % and IGF-II. The implications of these results on cancer recurrence or survival may become more evident with longer exercise intervention trials among breast cancer survivors.     

Neuron loss during early adulthood following prenatal low-dose X-irradiation in the mouse brain

Purpose : Apart from subsequent cell death, little is known about long-term effects of a prenatal low-dose X-irradiation (PLDI) on nuclear (n) and mitochondrial (mt) DNA, and whether these effects are connected with reduced neuron numbers in the adult brain. Materials and methods : Pregnant mice were X-irradiated with 0, 10 or 50cGy at day 13 (E13) of pregnancy. One day after (E14), or postnatally at day 25 (P25) or P180, the brains of the offspring were analysed concerning the extent of nDNA repair, mt biogenesis, and the relative content of nDNA single strand breaks (SSB). Stereology was applied for evaluating neuronal loss. Results : One day after irradiation no unrepaired SSB were detected. Significant results were mainly obtained for hippocampal pyramidal cells at P180, particularly cell loss following 50 cGy PLDI, increased SSB content and mt biogenesis (0 vs. 10cGy) but decreased mt biogenesis for 10 vs. 50 cGy. Conclusions : A hypothesis closely related to that regarding molecular events during aging is presented for explaining this second wave of cell death in adult mice following PLDI as a result of accumulated mtDNA damage caused by PLDI. A possible relation to the neurodegenerative hypothesis of schizophrenia is discussed.