Isolation of African swine fever virus from ticks of the Ornithodoros moubata complex (Ixodoidea: Argasidae) collected within the African swine fever enzootic area of Malawi

Ticks of the Ornithodoros moubata complex were collected from domestic pig sties and dwelling houses, and from a warthog habitat, and tested for the presence of African swine fever (ASF) virus. Collections were made in 9 of the 24 districts of Malawi, these being primarily the districts in which O. moubata is most numerous. ASF virus was isolated from ticks collected in both domestic pig sties and houses in certain villages in Mchinji district where ASF outbreaks had recently occurred. Mchinji district is in the centre of a large ASF enzootic area which stretches into other districts of Malawi and also into Zambia and Mozambique. The high titre of virus in some of the ticks demonstrates that O. moubata can act as a virus reservoir and potential vector of disease in the field situation in Malawi.     

Extracellular serotonin levels change with behavioral state but not with pyrogen-induced hyperthermia.

Extracellular 5-HT in the anterior hypothalamus/preoptic area (AH/POA) and caudate nucleus of the freely moving cat was measured using in vivo brain microdialysis. Administration of 8-OH-DPAT, a 5-HT1A receptor agonist that decreases 5-HT neuronal activity, decreased extracellular 5-HT in both brain areas. Extracellular 5-HT levels were also examined in relationship to the sleep-wake cycle, because previous data from our laboratory have indicated that behavioral state is the primary determinant of 5-HT neuronal discharge. As with 5-HT neuronal discharge, extracellular 5-HT was increased during active behavioral states and decreased during somnolent periods. These first two sets of findings confirm the ability of the microdialysis technique to measure physiological fluctuations in extracellular 5-HT levels and support the hypothesis that neuronal discharge is a major determinant of extracellular 5-HT levels. Levels of the 5-HT metabolite 5-hydroxyindole acetic acid (5-HIAA) in the AH/POA were also responsive to changes in behavioral state and administration of 8-OH-DPAT, though fluctuations in extracellular 5-HIAA were less robust and temporally delayed. Finally, extracellular 5-HT and 5-HIAA were examined in the AH/POA during fever induced by systemic injection of the synthetic pyrogen muramyl dipeptide. Previous data from our laboratory have indicated that 5-HT neuronal activity is unaffected by this manipulation, though 5-HT has been implicated specifically in thermoregulation. Pyrogen-induced hypothermia produced no specific change in 5-HT efflux, because any changes noted could be accounted for by behavioral state changes. These data are consistent with the hypothesis that the brain serotonergic system is closely linked to the sleep-wake-arousal cycle. However, extracellular 5-HT may be involved in thermoregulatory processes as part of a global role in modulating neuronal activity in coordination with the behavioral state of the animal.     

Benzodiazepine ([3H]flunitrazepam) binding in cat visual cortex: ontogenesis of normal characteristics and the effects of dark rearing

[3H]Flunitrazepam (FNZ) binding sites were characterized in homogenates of cat visual cortex during normal postnatal development and following dark rearing from birth. In parallel experiments, the distribution and density of [3H]FNZ binding sites were examined by in vitro autoradiographic or 'scrape' methods. In homogenates, Bmax measurements showed low early values, rising to a peak in receptor density at about 60 days postnatal, followed by a decline in adulthood. At all ages, gamma-aminobutyric acid (GABA) altered the Kd, but not the Bmax of [3H]FNZ binding sites. Kd values showed a general increase with age, parallelled by an increased sensitivity to GABA. Receptor autoradiography revealed that the highest density of [3H]FNZ binding sites was in layer IV of cats of all ages. Deafferentation of extrinsic inputs to the visual cortex by surgical undercutting did not alter this pattern of laminar distribution, indicating that the receptors were associated with intrinsic cortical elements rather than subcortical inputs. Dark rearing had no effect on [3H]FNZ laminar distribution in the visual cortex. The Bmax was higher at 30 days postnatal, but did not differ significantly thereafter. Modulation by GABA was concomitantly higher at 30 days, but lower than normal in dark-reared animals at ages greater than 30 days postnatal. The results are discussed in relation to the normal and abnormal development of GABA receptors in the cat visual cortex.     

Clinicopathologic correlation of pigmented epiretinal membranes

We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes.     

Zinc deficiency and hyperprolactinaemia are not reversible causes of sexual dysfunction in uraemia

We selected a group of male dialysis patients complaining of sexual dysfunction in whom penile vascular insufficiency and drug-induced impotence had been excluded. Monitoring of nocturnal penile tumescence was used to confirm organic disturbance. Patients with normal serum prolactin concentrations (n = 18) had significantly lower serum zinc values than normal controls (P less than 0.001) and were entered in a 6-month double-blind study comparing oral zinc acetate with placebo. Patients with elevated prolactin concentrations (n = 8) were entered in a 3-month double-blind crossover study comparing oral pergolide mesylate with placebo. In the zinc study, serum zinc concentrations increased (P less than 0.05) in the zinc-treated but not the placebo-treated group. One of nine patients receiving zinc reported improved sexual function, as did two of nine patients receiving placebo. There were no significant changes in sperm counts, nocturnal penile tumescence, testosterone, sex hormone binding globulin or gonadotrophin concentrations in either treatment group. In the pergolide study, serum prolactin values decreased (P less than 0.01) in the pergolide but not in the placebo treatment period. One patient reported improved sexual function during the pergolide treatment period and two during the placebo period. There were no significant changes in sperm counts, nocturnal penile tumescence, testosterone, sex hormone binding globulin or gonadotrophin concentrations after pergolide. These studies show no benefit of zinc or pergolide compared with placebo in the treatment of uraemic impotence.     

Biologic variation of common hematologic laboratory quantities in the elderly

Analytic, within-subject, and between-subject biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin content (MCHC), platelets, and a three-component differential count (lymphocytes, monocytes, and granulocytes in terms of both concentration and percentage of leukocytes) in cohorts of 12 male and 12 female healthy elderly subjects. The assays were performed with an Ortho ELT-800 automated analyzer. The estimates of within-subject biologic variation were similar to published data on young subjects, indicating that this aspect of homeostasis is not compromised in the elderly. The data were used to derive objective analytic goals; goals were surpassed except for assays of erythrocytes, hematocrit, and the derived MCV, MCH, and MCHC. The changes required for serial results to be significantly different were determined and found to be generally valid because most quantities have no heterogeneity of within-subject variation. All quantities had significant individuality; in consequence, conventional population-based reference values are of limited utility, and screening using reference limits will not detect latent or early disease in many subjects.     

Association of diurnal variations in hypothalamic but not cortical opiate ([3H]-naloxone)-binding sites with the ability of naloxone to induce LH release in the prepubertal female rat

We report the existence of a diurnal variation in the binding of the opiate antagonist [3H]-naloxone to slices of the mediobasal hypothalamus from prepubertal female rats. The binding is highest in the early morning and reaches a nadir in the late afternoon. Opiate binding in cortical slices from such animals is constant over the course of the day. Changes in receptor density, and not in receptor affinity, account for the diurnal variation in the amount of ligand bound. These diurnal variations in receptor numbers are associated with changes in the ability of naloxone to release LH and may be crucial in the transition from the juvenile state to one of competent reproductive functioning.