Enkephalin enhances responsiveness to perforant path input while decreasing spontaneous activity in the dentate gyrus

The opioid peptide [D-Ala2-Met5]-enkephalin-amide (DAMEA) was electrophoretically applied to the dentate gyrus in vivo to investigate opioid effects on evoked responsiveness to perforant path input and on spontaneous granule cell activity. DAMEA increased the amplitude of population spikes evoked by stimulation of the perforant path, and decreased sequential (recurrent or feed-forward) inhibition as determined by a paired-pulse paradigm. However, DAMEA concurrently inhibited spontaneous activity of individual granule cells. The effects of DAMEA on population and unit responses were antagonized by intravenous naloxone. These results confirm previous findings of opioid enhanced responsiveness to perforant path input and decreased sequential inhibition, but demonstrate a paradoxical inhibition of spontaneous unit activity by opioids in the granule cell layer.     

Chronic Social Stress in the Community and Associations with Psychological Distress: A Social Psychological Perspective

Chronic social stress is strongly related to psychological distress in vulnerable groups such as the frail elderly and ill people. Little, however, is known about these phenomena in the general population. The validity and reliability of a new brief measure, the Bergen Social Relationships Scale (BSRS), were investigated in a Norwegian county; the prevalence of chronic social stress was measured using the BSRS, and the associations of chronic social stress and social support with three measures of psychological distress were investigated. Respondents with high BSRS scores had experienced longstanding, important interpersonal relationship problems rather than fleeting stressful incidents. Women reported higher levels of chronic social stress, 60% reporting positively on at least one of the six BSRS items, compared with 50% among men. Social support was negatively and significantly associated with various measures of psychological distress. Chronic social stress was positively and significantly associated with psychological distress. These effects were independent of one another. No buffering effect of social support on social stress was observed. The present data support the importance of positive social ties to health, but suggest that social stress is an independent aspect of social environment with regard to health. If social support and social stress have direct and independent effects on mental health, as the present results indicate, intervention on the one will not necessarily modify the other. Intervention programmes may need to consider explicitly both the lighter and the darker sides of social relationships in building environments that support mental health.     

Airway intervention in adult supraglottitis

Background The timing of aggressive airway intervention in adult epiglottitis is controversial. Aims To correlate Friedman’s staging of epiglottitis on admission with the airway interventions undertaken. Methods A retrospective study of 23 adult patients, mean age 51 years (range 29–81 years), who had been admitted with acute supraglottitis between March 1988 and December 2000 was undertaken. Results Three patients (13%) had airway interventions; two with tracheostomy and one with tracheal intubation. All were Friedman stage III and had rapid symptom progression during the 24 hours prior to admission. Three other stage III patients with symptom progression longer than 24 hours and all the remaining patients (stage II or less) were managed with observation and intravenous therapy. Conclusions Friedman originally advocated airway intervention in any patient stage II or worse, but this intubation threshold should probably be lowered to those patients with rapid-onset stage III (moderate respiratory distress, stridor, respiratory rate >30 per minute, pCO₂ >45mmHg) disease.     

Gonadotropin therapy of female infertility

Anovulatory infertility in 134 women was treated with gonadotropins for a total of 318 cycles. The patients were classified into WHO group I, hypothalamic-pituitary failure (72 patients), and WHO group II, hypothalamic-pituitary dysfunction (62 patients). All patients in this group had failed to achieve pregnancy with clomiphene citrate therapy in repeated cycles. The pregnancy rate in group I was 72.2% vs 17.7% in group II. The 'take home' baby rate was 57.1% in group I vs 13.1% in group II. The rate of miscarriages was 14.3% without any significant difference between the groups. Multiple pregnancies occurred only in group I patients (19.2%). The conception rate was highest in the first four cycles, whereas no patient became pregnant after the sixth treatment cycle. Ovarian hyperstimulation syndrome occurred most frequently in group II patients, however, overall only 2.2% of the patients needed hospitalization because of hyperstimulation. Gonadotropin therapy must be considered an efficient and successful treatment of infertility in patients with hypothalamic-pituitary failure, whereas the success rate is rather poor in patients with hypothalamic-pituitary dysfunction.     

An occipito-temporal syndrome in adolescents with optimally controlled hyperphenylalaninaemia

Summary The study included 16 adolescents with optimally controlled hyperphenylalaninaemia (McKusick 26160), of whom six did not require treatment according to conventional criteria. All except the two patients with lowest median serum phenylalanine level throughout childhood (most values at 200–300 µmol/L) had white matter abnormalities detectable with magnetic resonance imaging. The lesions were particularly prominent in the watershed regions between the posterior and middle cerebral arteries. In most patients with moderate or severe hyperphenylalaninaemia frontal white matter lesions were present as well. Normal proton magnetic resonance spectra indicated that the lesions were stable. Occipital EEG abnormalities were frequent, and deficient performance on a pattern-recognition test was a characteristic neuropsychological finding. Serum phenylalanine levels at about 300 µmol/L or below throughout childhood and early adolescence may be required to avoid lesions. The present study demonstrates the limitations of even an optimally controlled dietary regimen in hyperphenylalaninaemia.     

The hematopoietic stem cells of alpha-thalassemic mice

The alpha-thalassemic mouse has a hereditary microcytic anemia, almost certainly has a shortened RBC life span, and is a potential candidate for cell replacement therapy. In a routine study of bone marrow repopulating capacity using hemoglobin as a cell marker, normal donor marrow cells, but not alpha-thalassemic donor marrow cells, completely replaced the host cells. Further analysis showed that at least 30 times more alpha-thalassemic cells were required to outcompete normal donor cells injected simultaneously. The results were more extreme then expected and suggested a defect in a stem cell population as well as in the RBCs. Evidence that the multipotent and erythroid-committed stem cells in alpha-thalassemic mice are not decreased was shown by CFU-S and CFU-E assays. The combined results indicate that the deletion expresses itself most conspicuously in the RBC population. Tests were also performed to analyze repopulation kinetics in the Hbath-J/+ mice. In unirradiated alpha-thalassemic hosts, the hemoglobin from a normal donor persisted but did not replace the host hemoglobin. Sublethally irradiated alpha-thalassemic hosts, on the other hand, were easily repopulated with normal cells. We conclude that the alpha-thalassemic mouse is a good model for cell replacement therapy.