The critical role of persistent sodium current in hippocampal gamma oscillations.

Gamma network oscillations in the brain are fast rhythmic network oscillations in the gamma frequency range (~30-100 Hz), playing key roles in the hippocampus for learning, memory, and spatial processing. There is evidence indicating that GABAergic interneurons, including parvalbumin-expressing basket cells (PVBCs), contribute to cortical gamma oscillations through synaptic interactions with excitatory cells. However, the molecular, cellular, and circuit underpinnings underlying generation and maintenance of cortical gamma oscillations are largely elusive.

Group I metabotropic glutamate receptors generate two types of intrinsic membrane oscillations in hippocampal oriens/alveus interneurons.

GABAergic interneurons in the hippocampus are critically involved in almost all hippocampal circuit functions including coordinated network activity. Somatostatin-expressing oriens-lacunosum moleculare (O-LM) interneurons are a major subtype of dendritically projecting interneurons in hippocampal subregions (e.g.

Cell Type-specific Intrinsic Perithreshold Oscillations in Hippocampal GABAergic Interneurons.

The hippocampus plays a critical role in learning, memory, and spatial processing through coordinated network activity including theta and gamma oscillations. Recent evidence suggests that hippocampal subregions (e.g.

Development of the sexually dimorphic nucleus of the preoptic area and the influence of estrogen-like compounds.

One of the well-defined sexually dimorphic structures in the brain is the sexually dimorphic nucleus, a cluster of cells located in the preoptic area of the hypothalamus. The rodent sexually dimorphic nucleus of the preoptic area can be delineated histologically using conventional Nissl staining or immunohistochemically using calbindin D28K immunoreactivity. There is increasing use of the bindin D28K-delineated neural cluster to define the sexually dimorphic nucleus of the preoptic area in rodents.

Historical reminiscence: origin of the Greenfield filter.

The Greenfield filter was the result of collaboration between a surgeon and a petroleum engineer. Originally it was a component of a catheter management approach to massive pulmonary embolism. Industry support allowed further technical improvements and long-term patient followup studies.

Aneurysm-related mortality rates in the US AneuRx clinical trial.

Background: The AneuRx (Medtronic) stent graft was approved by the FDA in September 1999. The purpose of this study was to ascertain the aneurysm-related mortality rate of a subgroup of the patient cohort from Medtronic's investigational premarket study.

Study Design: There were 931 study subjects, from 19 medical centers, who were followed for an average of 3.

Cognitive functioning, retirement status, and age: results from the Cognitive Changes and Retirement among Senior Surgeons study.

Background: Accurate assessment of cognitive functioning is an important step in understanding how to better evaluate both clinical and cognitive competence in practicing surgeons. As part of the Cognitive Changes and Retirement among Senior Surgeons study, we examined the objective cognitive functioning of senior surgeons in relation to retirement status and age.

Study Design: Computerized cognitive tasks measuring visual sustained attention, reaction time, and visual learning and memory were administered to both practicing and retired surgeons at annual meetings of the American College of Surgeons.

The spectrum of arterial compression at the thoracic outlet.

Objective: In the absence of ischemic events, arterial pathology at the thoracic outlet (TO) is rarely identified because findings of chronic arterial pathology may be masked by symptoms of neurogenic compression. This study describes the clinical presentations and significance of arterial compression at the TO.

Methods: This was a retrospective analysis of the clinical records and imaging studies of 41 patients with objective findings of arterial compression at the TO.

Results from the cognitive changes and retirement among senior surgeons self-report survey.

Background: The Cognitive Changes and Retirement among Senior Surgeons (CCRASS) study suggested that although subjective cognitive awareness may play a role in surgeons' retirement decisions, self-perceived cognitive decline did not predict objective cognitive performance. This article summarizes results from all participants who completed the survey portion of the CCRASS study.

Study Design: A survey examining subjective cognitive changes, changes in caseload, involvement in new technology, and retirement decisions, was administered to 995 surgeons at annual meetings of the Clinical Congress of the American College of Surgeons between 2001 and 2006.

Cognitive changes and retirement among senior surgeons (CCRASS): results from the CCRASS Study.

Background: Because individuals age cognitively at different rates, there is considerable interest in ways to assure that older surgeons have the physical and mental stamina, coordination, reaction time, and judgment to provide appropriate care. To clarify potential relationships between cognitive changes related to aging, the decision to retire, and changes in patterns of surgical practice, this study aimed to identify specific parameters of cognitive change among senior surgeons.

Study Design: Computerized cognitive tasks measuring sustained attention, reaction time, visual learning, and memory were administered to 359 surgeons at the annual meetings of the American College of Surgeons over a 6-year period.

Form and function of vena cava filters: how do optional filters measure up?

The function of vena cava filters, preventing pulmonary embolism while maintaining caval patency, is associated with the design. Several characteristics have been reported. This report evaluates retrievable filter designs in comparison with previously marketed designs with respect to efficacy and safety.

Acute venous disease: venous thrombosis and venous trauma.

Acute venous disorders include deep venous thrombosis, superficial venous thrombophlebitis, and venous trauma. Deep venous thrombosis (DVT) most often arises from the convergence of multiple genetic and acquired risk factors, with a variable estimated incidence of 56 to 160 cases per 100,000 population per year. Acute thrombosis is followed by an inflammatory response in the thrombus and vein wall leading to thrombus amplification, organization, and recanalization.

Surgeons outperform normative controls on neuropsychologic tests, but age-related decay of skills persists.

Background: The present study was undertaken to determine if psychomotor and visual-spatial abilities improve as a result of surgical training or are enhanced at baseline in those individuals choosing a surgical career.

Methods: Medical students entering a surgical field and practicing surgeons performed a series of neuropsychologic tests. Performance was compared between surgeon groups, as well as with normative aged-matched controls.

Medical liability-the crisis, the reality, and the data: the University of Michigan story.

Background: This study describes, quantifies, and evaluates the University of Michigan Department of Surgery medical malpractice experience for the 1992 to 2002 period. The goal is to gain an understanding of what our claims experience has been, what services are highest risk, and where the financial exposure lies.

Study Design: The study analyzed 308 medical malpractice cases within the Department of Surgery from 1992 through 2002.

Surgeon age and operative mortality in the United States.

Objectives: Although recent studies suggest that physician age is inversely related to clinical performance in primary care, relationships between surgeon age and patient outcomes have not been examined systematically.

Methods: Using national Medicare files, we examined operative mortality in approximately 461,000 patients undergoing 1 of 8 procedures between 1998 and 1999. We used multiple logistic regression to assess relationships between surgeon age (< or =40 years, 41-50 years, 51-60 years, and >60 years) and operative mortality (in-hospital or within 30 days), adjusting for patient characteristics, surgeon procedure volume, and hospital attributes.