Rapid cortical hemoglobin deoxygenation after heroin and methadone injection in humans: a preliminary report.

The short-term effects of intravenous opioids (heroin 20-300 mg, methadone 30-180 mg) on cortical hemoglobin oxygenation were examined by near infrared spectroscopy in ten opioid-dependent subjects and were compared with the effects of saline in ten age-matched normal controls. Heroin and methadone produced a rapid and dramatic decrease in cortical hemoglobin oxygenation. Saline had no effects. Opioid-induced acute deoxygenation of cortical hemoglobin is most likely associated with respiratory depression. Thorough medical monitoring is strongly recommended in intravenous opioid maintenance treatments.

[Fine structure of the raphe nuclei of sheep and goats]. / Zur Feinstruktur der Raphekerne von Schaf und Ziege.

The medullary raphe system of sheep and goat can be divided in the solitary nuclei raphe magnus and pallidus besides the impaired Nucleus raphe paramedianus. The nucleus raphe magnus begins in the caudal end of the medulla oblongata running far to the pons. On the other hand you can follow the nucleus raphe pallidus and paramedianus only in distinct area near the obex. Different types of neurons are isolated and described in light- and electronmicroscopical investigations. All three nuclei are poor of synapses.

Auditory distraction in young and middle-aged adults: a behavioural and event-related potential study.

Cognitive tasks involving distraction are associated with an early age-related decline in performance. Involuntary shifts in attention to irrelevant stimulus features and subsequent reorientation were studied in young and middle-aged subjects focussing on behavioural and event-related potential (ERP) measures. Subjects were asked to discriminate between equiprobable short and long auditory stimuli. Irrelevant rare frequency deviations prolonged reaction times (RT's), while an age-related effect on RT's was not observed. In contrast, notably after short deviant tones the error rate was considerably increased in the middle-aged subjects. ERP measures after deviant stimuli elicited a sequence of mismatch negativity (MMN), P3a and reorienting negativity (RON). The latency and amplitude of the MMN did not differ between age groups indicating an unchanged deviance detection. However, the consecutive process of attention orientation (P3a) was delayed and the subsequent reorienting (RON) to the primary task was strongly attenuated in the middle-aged subjects. After short deviants the RON was virtually absent in the middle-aged subjects, which might account for the observed decline of accuracy.

Modification of virtual reality combined with a mental task stimulates cortisol in volunteers.

Immersive, stereoscopic virtual reality (VR) systems provide a powerful multimedia tool for a laboratory simulation of distinct scenarios including stressful situations close to reality. Thus far, cortisol secretion as a neuroendocrine parameter of stress has not been evaluated within a VR paradigm. Ninety-four healthy subjects were subjected to a VR paradigm and a cognitive stress task. It was tested (a) if the modification of reality induced by dynamic VR as opposed to static VR can be regarded as a stressor and (b) if it can modify an additional cognitive stress response. In addition, the impact of gender on cortisol responses was assessed. A significant cortisol increase was observed only after the combined application of both conditions, but not after the dynamic VR or the cognitive stress alone. Cortisol reactivity was greater for men than for women. We conclude that dynamic VR does not affect cortisol secretion per se, but increases cortisol responses in a dual task paradigm. This provides the basis for the application of VR in neuroscientific research, which includes the assessment of hypothalamus-pituitary-adrenal axis regulation.

[The ultrastructure of the nucleus of the solitary tract of the sheep and goat]. / Zur Feinstruktur des Nucleus tractus solitarii von Schaf und Ziege.

The sensory nucleus of the IXth and Xth cranial nerve in sheep and goat takes a position in the middle of the elongated medulla forming a bilateral symmetric cell column. Neighbouring the canalis centralis dorsolaterally the caudal segments of both nuclei are connected in the raphe region by a subnucleus commissuralis. The solitary tract defines the nucleus in its lateral extension. The area postrema limits the rostral pole from the surface. Two distinct types of neurones are observed in the light and electron microscope. The small neurones show a paucity of organelles and an invaginated nucleus. According to their synaptic density three variations of small neurones could be distinguished. The large neurones are more compact in their cytoplasmic organisation. According to their size and morphology of vesicles five types of synaptic boutons could be differentiated. Most of the profile of the perikarya is surrounded by astrocytes and their extensions.

[The fine structure of the nucleus of the hypoglossal nerve of sheep and goats]. / Zur Feinstruktur des Nucleus nervi hypoglossi von Schaf und Ziege.

In the small domesticated ruminants the nucleus of the hypoglossal nerve is situated in close relationship to the median line in the middle of the elongated medulla. The nucleus is divided by the obex into a rostral and a caudal portion. In the sheep, four distinct subnuclei can be recognized, whereas in the dwarf goat great variations in the arrangement of cell groups exists. In both animals large and medium sized neurons are observed. The large neurons are characterized by densely packed small organelles. The medium sized neurons vary between a pale and an electron dense type. According to the size and morphology of the vesicles three types of synaptic contacts can be differentiated. Synapses of type 2 contain clear round and flattened vesicles and are partially accompanied by subsurface cisterns.

Differences in antimicrobial susceptibility of pigmented and unpigmented colonial variants of Mycobacterium avium.

Unpigmented colonial variants were isolated from pigmented Mycobacterium avium isolates recovered from patients with acquired immunodeficiency syndrome and the environment. The variants were interconvertible: the rate of transition from unpigmented to pigmented type was 4.0 x 10(-5) variants per cell per generation. The unpigmented variants were more tolerant to antibiotics, especially beta-lactams, and Cd2+ and Cu2+ salts than were their pigmented parents. Both pigmented and unpigmented variants of the strains produced beta-lactamase, although beta-lactamase did not appear to be a determinant of beta-lactam susceptibility. Pigmented variants grew more rapidly in a number of commonly used mycobacterial media, were more hydrophobic, and had higher carotenoid contents than their unpigmented segregants.

[The fine structure of the nucleus of the facial nerve of sheep and goats]. / Zur Feinstruktur des Nucleus nervi facialis von Schaf und Ziege.

The nucleus of the facial nerve in sheep and goats measures 4 to 6 mm and is divided into 4 groups (dorsal, medial, lateral, intermediate). Electronmicroscopically 5 neuronal types and 4 classes of synapses could be detected. Differences between the species are reduced to the arrangement of the rough endoplasmic reticulum and number of axo-somatic synapses.

[Treatment of acrophobia in a virtual environment]. / Die Behandlung der Höhenangst in einer virtuellen Umgebung.

Specific phobias are one of the most frequent mental health problems and can lead to years of personal suffering. The most effective treatment is exposure therapy. Our aim was to proof the feasibility and efficacy of virtual environments in treating acrophobia patients using a manually guided exposure therapy. Our pilot study was designed as a crossover intervention with a waiting list condition as a control group. After treatment, our results show that exposure in virtual environments is a feasible technique, can provoke anxiety, and leads to a therapeutic effect.