Effects of lactate-induced panic attacks on brain stem auditory evoked potentials

As the clinical symptomatology of panic attacks may be conceivably related to abnormal brain stem activity, the present study examined the effect of lactate-precipitated panic on brain stem auditory evoked potentials (BSAEPs). The subjects were 27 patients who met DSM-III criteria for panic disorder (Pd), agoraphobia with panic attacks (AgPa) or agoraphobia (Ag). Following drug washout, patients were tested in two separate sessions, in a double-blind randomised controlled design in which each session involved two sequentially ordered BSAEP collection periods - a baseline period with no infusion followed by an intravenous infusion of 5% dextrose in water or 1.0 M sodium lactate (5 ml/kg in 5% dextrose/water) over a 20-min period. Of the 27 patients, 17 were clear responders, reporting panic attacks and self-report changes under lactate similar to those occurring during spontaneous panic. Of the remaining 10 patients, 6 were pseudo-responders, reporting panic symptoms under both dextrose and lactate, and 4 were non-responders. In the clear responders, lactate did not alter electrical events of the BSAEP, but further analysis within the clear responders, comparing AgPa patients with Pd patients, yielded a significant effect with lactate resulting in a prolonged III-V inter-peak interval in the AgPa group. It is suggested that the increased III-V interval in the AgPa group may be reflective of hyperactivity of brain stem noradrenergic nuclei.     

EEG and the passive P300 in dementia of the Alzheimer type.

Quantitatively analyzed resting electroencephalographic (EEG) activity and P300 event-related potentials elicited with a passive tone sequence paradigm were examined in 30 patients with dementia of the Alzheimer type (DAT) and 15 age matched controls. Background electrical rhythms of DAT patients evidenced slowing as shown by increased absolute and relative amplitudes in slow frequency bands and decreased amplitudes in fast frequency bands (relative to controls). Electrical slowing was more evident in patients with higher clinical ratings of global intellectual deterioration. Passive P300 amplitude and latency did not differentiate patients and controls and were not related to severity of dementia.     

Serological studies with influenza A(H1N1) viruses cultivated in eggs or in a canine kidney cell line (MDCK)

Pairs of influenza A(H1N1) viruses cultivated from the same clinical specimen in canine kidney (MDCK) cells or in embryonated hens'' eggs can frequently be distinguished by their reactions with monoclonal antibodies to haemagglutinin and with antibodies in ferret or human sera. Egg-adapted virus, further passaged in MDCK cultures remained ”egg-like” in serological characteristics indicating that the differences in their serological reactions were not a direct result of host cell-dependent glycosylation of the haemagglutinin. Haemagglutination-inhibiting (HI) or virus neutralizing antibodies in human sera can be detected more frequently, and to higher titre, in tests employing virus grown exclusively in MDCK cells than in tests with virus adapted to growth in embryonated eggs. Striking differences were detected in the serological reactions in HI tests when sera from ferrets infected with egg-grown virus were tested against a series of strains of influenza A(H1N1) virus isolated in 1983 and adapted to growth in eggs. In contrast, sera from ferrets infected with MDCK-derived virus failed to distinguish serologically between the same viruses that had been passaged exclusively in MDCK cells and also revealed relatively small differences between their egg-adapted counterparts.     

Transdermal nicotine: single dose effects on mood, EEG, performance, and event-related potentials.

A 21-mg dose of nicotine was administered transdermally to 16 overnight smoking-deprived smokers in a double-blind, placebo-controlled design. Mood ratings, electroencephalography (EEG), behavioral performance and event-related potential (ERP: P300) indices of attention and information processing speed were assessed before and 4 h after placebo/nicotine treatment. Although nicotine, relative to placebo, failed to alter mood, it increased absolute and relative power indices of EEG arousal, shortened reaction times, and increased P300 amplitudes. The results are discussed in relation to nicotine's actions on cholinergic transmission and its role in smoking behavior.     

Distribution in female rats of an anaesthetic intravenous dose of 14C-propofol.

1. Bolus i.v. doses of 14C-propofol (9 mg/kg) were administered to female rats for measurement of tissue levels of total 14C and propofol from 2 min to 24 h post-dose; whole-body autoradiography was studied at 6 min, 2 h and 24 h post-dose, and also involved 15-day pregnant rats. 2. The blood propofol concentration-time profile was fitted by a tri-exponential function corresponding to a three-compartment open model. Data show rapid distribution during the mixing period into highly perfused tissues and muscle, comprising the central compartment, and slower uptake into less well-perfused skin and adipose tissues comprising the deeper compartments. 3. The initial decline in blood propofol concentration was associated with redistribution (t1/2 4 min), the second decline (15-240 min post-dose) was associated with metabolism (t1/2 33 min) and the third decline reflected slow depletion of drug from deep tissue compartments (t1/2 6.4 h). 4. Blood and brain propofol concentrations on waking (at 7 min post-dose) were 4 micrograms/ml and 9 micrograms/g respectively; the model shows that, at this time, 30% of the dose was lost from the central compartment by redistribution and a similar amount by metabolism. 5. Tissue profiles of total 14C and propofol diverged for highly perfused tissues (other than brain) because of slow clearance of metabolites, accentuated by enterohepatic recirculation.     

Hippocampal-dependent familiar area map supports corrective re-orientation following navigational error during pigeon homing: a GPS-tracking study

It is hypothesized that a central role of the vertebrate hippocampal formation (HF) in behavior is the learning and operation of a map-like representation of familiar landmarks and landscape features. One critical property of a map is that it should enable an individual to re-orient towards a goal location following a navigational error. To test this prediction on a spatial scale consistent with their naturally occurring behavior, control and HF-lesioned homing pigeons were trained from two locations and then subsequently released, while carrying portable GPS-tracking devices, following a phase-shift treatment. Analyses revealed that the HF-lesioned pigeons were less successful than control pigeons in re-orienting homewards following the phase-shift-induced error in their initial orientation. Furthermore, the observation that HF-lesioned pigeons were found to routinely ignore a land–sea landscape boundary when returning home from one of the release sites suggests that coarse landscape features may be an underappreciated source of navigational information for homing pigeons. The data demonstrate that, on a scale of tens of kilometers, homing pigeons are able to learn a hippocampal-dependent, map-like representation of familiar landmarks/landscape features that can support corrective re-orientation following a navigational error.     

Genetic linkage between the antigenic group (Ag) variation and the apolipoprotein B gene: assignment of the Ag locus.

The antigenic group (Ag) system of homospecific human serum antigens of low density lipoprotein is detected by antiserum from multiply transfused patients. A complex series of common Ag alleles has been described, but the biochemical nature of this polymorphism is uncertain. Here we report that DNA polymorphisms at the human apolipoprotein B (apoB) locus are very closely linked to alleles of the Ag system. We also show a strong association between Ag(x) and a polymorphism detected with the restriction endonuclease Xba I. We conclude that the immunologically determined Ag system represents protein polymorphism of apoB rather than primary genetic differences in posttranslational processing or lipid binding. These studies therefore demonstrate that the Ag locus is located on the short arm of human chromosome 2 in the region p23-p24 to which the apoB gene has been assigned. Since the Ag(x) antigen is associated with altered plasma lipid levels, this determinant may indicate a functionally important domain of apoB.