Hippocampal hypoglycaemia-activated K+ channels: single-channel analysis of glucose and voltage dependence

The effect of glucose on kinetics and the voltage-dependent characteristics of glucose-sensitive channels in hippocampal neurons were examined with the cell-attached mode of the patch-clamp technique. Recordings of a 100-pS K⁺ channel in the presence or absence of glucose demonstrate that the increase in channel open state probability (P _o) induced by glucose deprivation (40- to 400-times the control in high-glucose medium) was largely due to a decrease in the global amount of time spent by the channel in a long-lived closed state. TheP _o value of the same 100-pS channel was also found to increase (by approx. 80-times) following a depolarization of 40 mV from rest, the main factor responsible for this being a dramatic shortening of the long closed-times on depolarization. Another glucose-sensitive channel of smaller conductance (approx. 10 pS) showed a similar dependence ofP _o on glucose, but different dependence on voltage, with long openings at the same hyperpolarized potentials where the 100-pS channel was almost always closed. Our results indicate that the action of glucose on the kinetics of hippocampal channels closely resembles that of ATP-sensitive channels in pancreaticβ-cells. Furthermore, they indicate that the two types of glucose-sensitive channels found in hippocampal neurons, differing not only in their single-channel conductance but also in the dependence on voltage, could play different roles in the responses of these cells to modified energetic supply.     

Genetic Basis of Acquired Immunodeficiency Syndrome-Related Lymphomagenesis

The molecular pathogenesis of systemic acquired immunodeficiency syndrome(AIDS)-related non-Hodgkin's lymphomas (AIDS-NHL) is a complexprocess involving both host factors and the accumulation ofgenetic lesions within the tumor clone. On the basis of thepattern of molecular lesions involved in these tumors, severaldistinct pathogenetic pathways can be presently identified inAIDS-related lymphomagenesis. These pathways selectively associatewith the different clinicopathologic variants of AIDS-NHL. AIDS-relatedBurkitt's lymphoma is characterized by activation of c-MYC inall cases, disruption of p53 in 60% of the cases, and infectionby Epstein-Barr virus (EBV) in 30% of the cases. AIDS-relateddiffuse large-cell lymphoma harbor frequent EBV infection (80%) and,in 20% of the cases, BCL-6 rearrangements. Finally, the pathogenesisof AIDS-related body cavity-based lymphoma involves infectionby human herpesvirus-8 in all cases and frequently also theco-infection by EBV.     

Retroperitoneal abscesses — rare causes and atypical manifestations: Report of two cases

Retroperitoneal space abscesses are a life-threatening illness which is difficult to diagnose and treat because of both their rarity and insidious clinical manifestations. The insidious development of this illness is a challenge for all medical and surgical subspecialists. The discovery of the real source of the infection is very important but not always possible, and knowledge of the anatomy and borders of the retroperitoneal space is helpful in understanding all such atypical cases and for establishing a definitive treatment. Two cases are reported that are both characterized by rare causes, uncommon development, and atypical manifestation. The normally undefined inferior borders of some parts of the retroperitoneal space or previous retroperitoneal surgery could have been the cause of the abnormal and misleading development of the abscesses. Chronically infected organs can be the true origin of this abscess, and their discovery in a nonemergency situation is mandatory for complete surgical treatment. These cases show that knowledge of the anatomy of the retroperitoneal space is important to establish the suspicion of an abscess, to understand its manifestations, which are sometimes caused by a rare pathophysiology, and to initiate appropriate treatment.     

Intracardiac migration of nitinol TrapEase vena cava filter and paradoxical embolism.

The nitinol TrapEase inferior vena cava filter is a new device for pulmonary embolism prophylaxis. No cases of filter migration or filter-related complications with this type of device have so far been described. We report a case of intracardiac migration of this filter in a patient with a patent foramen ovale, resulting in severe cardiogenic shock, cerebral and right arm paradoxical embolism. Surgical treatment, results, causes of these complications are discussed.     

Two distinct intracranial tumors of different cell types in a single patient. Case report and review of the literature

We report the case of a patient with two distinct brain tumors. A meningioma was resected surgically. Nine months later a glioblastoma appeared in the same region, but at a different site. This was not treated, because the patient died. The clinical significance and etiology of these tumors are considered.