Developmental profile of erythropoietin and its receptor in guinea-pig retina

Evidence suggests that endogenous erythropoietin (EPO) is involved in the development of the central nervous system; however, its role in retinal development is yet to be determined. In this study, we have used fluorescence immunohistochemistry to localise EPO and its receptor (EPOR) in the developing and mature retina of the guinea-pig, a species in which retinal development is similar to that in humans. EPO immunoreactivity (IR) was observed in ganglion cells from 25 days of gestation (dg; term ∼67 dg), and in the inner and outer plexiform layers and in horizontal cells by 40 dg. EPO-IR persisted in all of these structures into adulthood. Müller cells also displayed EPO-IR, which was seen in the radial processes and endfeet at 40 dg and in the cytoplasm by 50 dg. IR in these cells was particularly intense and appeared to increase with age. EPOR-IR was found in all ages examined; it was detected in ganglion cells at 25 dg and, from 30 dg onwards, was localised on, and adjacent to, the cell surface membrane. The distribution of EPOR-IR became increasingly widespread during gestation and, by 50 dg, EPOR-IR was detectable on the majority of retinal somal membranes. This localisation persisted in the postnatal and adult retina. Therefore, IR for EPO and its receptor is present in the guinea-pig retina from as early as 25 dg, when retinal layers are forming, and persists throughout postnatal development. This suggests that EPO plays a role both in retinal development and in the maintenance of the adult retina. This study was funded by the ANZ Charitable Trust; Medical Research and Technology in Victoria (M. Tolcos) and the National Health and Medical Research Council of Australia (M. Tolcos).     

Lymphangioma. A long-term follow-up study.

At the Hospital for Sick Children 177 patients with lymphangioma, exclusive of those who had intra-abdominal lesions, were seen between 1927 and 1964. Forty-nine of these (aged 8 to 41 years) were available for follow-up examination. The results of treatment by surgical excision, aspiration, incision and drainage, and radiation are reported. No cases confirmed histologically as lymphangioma underwent spontaneous regression. Two histologically unconfirmed cases underwent partial regression. Four of the 11 who were left with lymphangioma tissue at operation never had significant recurrences. Therefore, this clinical study does not clarify the possible role of spontaneous regression in lymphangioma. Extensive surgery is the treatment of choice whenever feasible, but in unilocular or bilocular cystic lymphagnioma subsequent regression can be expected after palliative treatment (aspiration, or incision and drainage). Clinical and pathological criteria should be established for differentiation between lymphangioma and primary lymphedema. Lesions involving subepithelial, subdermal, and subcutaneous or internodal networks of lymphatics will produce lymphagioma; lesions of the collecting lymphatic trunks will result in lymphedema.     

Nutritional requirements of anaerobic spirochetes. I. Demonstration of isobutyrate and bicarbonate as growth factors for a strain of Treponema microdentium

Hardy, Paul H., Jr. (The Johns Hopkins University School of Medicine, Baltimore, Md.), and Carole O. Munro. Nutritional requirements of anaerobic spirochetes. I. Demonstration of isobutyrate and bicarbonate as growth factors for a strain of Treponema microdentium. J. Bacteriol. 91:27-32. 1966.-The previously reported ability of a microaerophilic diphtheroid to support the growth of some oral spirochetes resides in the acid-distillable fraction of the culture fluid. This fraction can be replaced by isobutyrate and, to a lesser extent, by 2-methylbutyrate. When media are supplemented with isobutyrate alone, there is a prolonged lag phase before spirochetal growth commences, but when sodium bicarbonate is also added the lag phase is shortened, and both the growth rate and the total yield are increased. Serum, in low concentration, also acts as a growth stimulant, but it is inhibitory when present at higher concentrations.     

The identification of chemicals involved in the interaction of Oscinella frit with Avena sativa

Oscinella frit have been reared in large numbers over a 2-year period using oat plants as host. The attraction between frit fly and oat shoots can be said to be partly visual and partly chemical. Extraction of oat plants with four solvent systems, e.g. 80% ethanol, acetone, chloroform: methanol and chloroform enabled an active fraction to be obtained which attracts frit fly. A synergistic interaction between the lipid and non-lipid fraction of oats is reported for the first time. The lipid material has been separated and the substance suspected to be responsible for the attraction of frit fly has been classified as a hydroxybetadiketone.

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Résumé Oscinella frit a été élevé en grand nombre pendant une période de 2 ans sur pieds d'avoine. L'influence des pousses d'avoine sur la Mouche de Hesse peut être considérée comme partiellement visuelle et partiellement chimique. L'extractio par quatre types de solvants (éthanol à 80%, acétone, chloroforme-éthanol, chloroforme) permet d'obtenir une fraction active attirant les mouches. Une interaction synergique entre les fractions lipidiques ou non des pousses d'avoine, a été observée pour la première fois. La partie lipidique a été analysée et la substance vraisemblablement attractive a été identifiée comme une hydroxybetadiketone.

     

IN VIVO INHIBITION OF RAT BRAIN PROTEIN SYNTHESIS BY d-AMPHETAMINE

Abstract— Between 1 and 4 h after rats received a single injection of d-amphetamine (15 mg/kg)(when brain polysomes are known to be disaggregated), the in vivo incorporation of [¹⁴C]lysine into trichloroacetic acid-precipitable brain protein was reduced by 28–48%. Incorporation of the ¹⁴C label into the protein present in a 100,000 g supernatant extract of whole brain was similarly reduced (by 44%). Amphetamine administration suppressed protein synthesis in rat cerebral cortex, cerebellum, hypothalamus, striatum, and brainstem to an equivalent extent. The drug did not significantly affect lysine pool sizes measured in these brain regions; thus the reduced incorporation of labeled lysine was not the result of an isotope dilution effect. We therefore conclude that the brain polysome disaggregation resulting from amphetamine administration is associated with decreased in vivo synthesis of some brain proteins.