The thalamic reticular nucleus in schizophrenia and bipolar disorder: role of parvalbumin-expressing neuron networks and oxidative stress.

Growing evidence points to a disruption of cortico-thalamo-cortical circuits in schizophrenia (SZ) and bipolar disorder (BD). Clues for a specific involvement of the thalamic reticular nucleus (TRN) come from its unique neuronal characteristics and neural connectivity, allowing it to shape the thalamo-cortical information flow. A direct involvement of the TRN in SZ and BD has not been tested thus far. We used a combination of human postmortem and rodent studies to test the hypothesis that neurons expressing parvalbumin (PV neurons), a main TRN neuronal population, and associated Wisteria floribunda agglutinin-labeled perineuronal nets (WFA/PNNs) are altered in SZ and BD, and that these changes may occur early in the course of the disease as a consequence of oxidative stress. In both disease groups, marked decreases of PV neurons (immunoreactive for PV) and WFA/PNNs were observed in the TRN, with no effects of duration of illness or age at onset. Similarly, in transgenic mice with redox dysregulation, numbers of PV neurons and WFA/PNN+PV neurons were decreased in transgenic compared with wild-type mice; these changes were present at postnatal day (P) 20 for PV neurons and P40 for WFA/PNN+PV neurons, accompanied by alterations of their firing properties. These results show profound abnormalities of PV neurons in the TRN of subjects with SZ and BD, and offer support for the hypothesis that oxidative stress may play a key role in impacting TRN PV neurons at early stages of these disorders. We put forth that these TRN abnormalities may contribute to disruptions of sleep spindles, focused attention and emotion processing in these disorders.

Natural history of isolated ventricular septal defect in the first five years of life.

BACKGROUND: Isolated ventricular septal defect (VSD) is the most common congenital heart defect. Incidence, prevalence, and clinical outcomes of VSD have been reported to vary significantly in different geographic areas. Spontaneous closure of VSD, in children, by various methods has been described. HYPOTHESIS: This prospective study was undertaken to evaluate natural history of patients with VSD in the first five years of life in the Northeast Tennessee and Southwest Virginia region. METHODS: Between December 1, 1998 and October 31, 1990, 124 infants were diagnosed clinically with isolated VSD. VSDs were classified as muscular, perimembranous, malalignment, or subpulmonic types by 2-dimensional echocardiogram with color flow mapping. Cardiac catheterization and angiocardiography were performed in 14 patients when clinically indicated. These patients were followed for at least five years. RESULTS: Overall spontaneous closure of VSD was 34% at one year and 67% at five years. Twenty-five percent of perimembranous and 4% of muscular VSDs required surgery by five years. The spontaneous closure rate of muscular VSD was twice that of the perimembranous type, though the relative distribution of both types was almost equal. Overall, 22% of children with VSD need follow-up after the fifth year of life. CONCLUSION: The overall clinical outcome of muscular VSD was consistently better than that of the perimembranous type, though 17% of muscular VSDs, irrespective of size, were open at 5 years of age and needed long-term follow-up.

Mediastinal bronchogenic cyst: diagnosis and follow-up.

A 5-year-old girl with an asymptomatic posterior mediastinal cyst from birth was followed with repeated echocardiograms. The cyst developed communication with the bronchus spontaneously around 8 months of age without clinical symptoms. This was detected from the sudden disappearance of the mass on echocardiogram, and an unusual air-pocket on chest roentgenogram. Computed tomography (CT) of the chest confirmed the diagnosis of communicating bronchogenic cyst (BC). She was treated successfully with complete surgical excision of the cyst and closure of the defect in the bronchus. We emphasize that surgery is indicated in all mediastinal BCs because of potential complications.

Antibody response to P-protein in patients with Branhamella catarrhalis infections.

Branhamella catarrhalis is now recognized as an important cause of lower respiratory tract infections, especially in the elderly. In most instances, pathogenicity is presumed by recovery of the organism in a sputum culture, a method that is less than conclusive. In order to better diagnose B. catarrhalis infections, an enzyme-linked immunoassay has been developed using P-protein as antigen to measure antibodies to B. catarrhalis. In 17 elderly patients with B. catarrhalis pneumonia and 12 with tracheobronchitis, acute-phase serum antibody titers to P-protein were found to be significantly increased when compared with those of normal subjects (both p less than 0.02). There were no differences in antibody titers between patients with pneumonia and tracheobronchitis. Antibody titers of convalescent-phase sera increased over those of acute-phase sera in 46 percent of pneumonia patients and 50 percent of tracheobronchitis patients. The results demonstrated that lower respiratory tract infections with B. catarrhalis promote a significant elevation in antibody response to P-protein of B. catarrhalis.

Susceptibility of dysgonic fermenter 2 to antimicrobial agents in vitro.

Dysgonic fermenter 2 (DF-2) is a fastidious, gram-negative organism well recognized as a cause of fulminant septicemia in patients without spleens or patients with alcoholic cirrhosis. In vitro antibiotic susceptibility testing of eight strains with a Schaedler broth dilution technique revealed DF-2 to be susceptible to all of the antibiotics tested except aztreonam. Previous reports that DF-2 is aminoglycoside resistant were based on disk diffusion or agar dilution assays that may be less reliable given the slow growth of the organism and its requirement for CO2 incubation. Penicillin is commonly used as prophylaxis after dog bites and has excellent activity against DF-2.