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Biomedical subjects

R Greenberg

Publications and source records attributed to R Greenberg.

At least 181 records · Page 10Linked to original sources
PubMed1979

Inhibition of passive lung anaphylaxis in the rat by AY-25,674.

The antiallergic properties of AY-25,674 were studied in a model of passive lung anaphylaxis. AY-25,674 caused a dose-related inhibition of antigen-induced bronchoconstriction in the passively sensitized rat. AY-25,674 was found to be twice as potent as disodium cromoglycate (DSCG) when injected intravenously. The oral administration of AY-25,674 also effectively inhibited antigen-induced bronchoconstriction. A tachyphylactic effect of repeated administration was found when the rats were pretreated with a large dose of AY-25,674. The compound did not significantly antagonize the bronchoconstriction produced by 5-hydroxytryptamine. These results indicate that AY-25,674 is an orally effective antianaphylactic compound with a mode of action similar to that of DSCG in preventing allergic mediator release.

Anaphylaxis↗
PubMed1978

Isolation, composition and ordering of cyanogen bromide peptides in human casein.

The major component of the casein fraction of human milk was cleaved by cyanogen bromide, and the composition of the resulting peptides was determined. Casein was also subjected to limited digestion by trypsin, and the amino acid composition of the isolated peptides was established. With this information the peptides were ordered as they occur in the purified protein.

Amino Acids↗
PubMed1978

The neuronal origin of prostaglandin released from the rabbit portal vein in response to electrical stimulation.

Transmural electrical stimulation of the isolated portal vein of the rabbit was accompanied by the release of a prostaglandin-like substance (PLS). Thin layer chromatography coupled with bioassay indicated that this substance was probably prostaglandin E2 (PGE2). 2 Indomethacin potentiated the response of the portal vein to electrical stimulation at 2 Hz and abolished the release of the PLS. 3 There was no significant change in the amount of PLS released from the portal vein in response to electrical stimulation at 2 Hz when the contractile response of the portal vein was prevented by pretreatment with phentolamine or guanthidine. 4 In vitro denervation of the portal vein with 6-hydroxydopamine or the omission of Ca2+ from the bathing solution caused a significant reduction in the amount of PLS released from the portal vein in response to electrical stimulation at 2 hertz. 5 It is concluded that electrical stimulation of the isolated portal vein of the rabbit is accompanied by the release of a PLS, probably PGE2, from a neuronal source. The synthesis and release of the PLS is Ca2+ -dependent.

Animals↗
PubMed1978

A method for selecting criteria to evaluate medical care.

This study tests a questionnaire method for eliciting process criteria for medical care appraisal. The questionnaire was sent to national samples of family physicians, pediatricians, and pediatricians specializing in infectious diseases asking their opinions about various clinical actions in 125 clinical situations concerning respiratory infection in infants. Five hundred twenty-four (54%) physicians returned completed questionnaires. Questionnaire responses favored the performance of a majority of actions and opposed very few. Opinions concerning individual actions, particularly diagnostic tests and treatments, varied widely depending upon the clinical situation presented. A second questionnaire sent one year later indicated that the opinions expressed in the first questionnaire remained stable over time, especially if the initial opinion favored performance of the action. Comparison of the questionnaire responses and medical records of a group of practitioners demonstrated that only 55% of actions favored in a practitioner's questionnaire appeared in his records. Although the questionnaire method appears to be a feasible, specific, and reliable means of identifying clinical opinion, there remains considerable discordance between opinion as expressed in the questionnaire and recorded clinical practice.

Humans↗
PubMed1978

In vitro assessment of interaction of blood with model surfaces.

An in vitro system for the assessment of blood compatibility of artificial surfaces is described. Anticoagulated human whole blood was pumped through columns of beads and then analyzed for evidence of platelet retention and the release of platelet constitutents. Platelets were retained on the columns by adhesion to the beads and by aggregation. Experiments were conducted with PVAc, PC, PMA and PS beads to provide data on the reproducibility of the system and the effects of anticoagulants and RBC concentration on platelet adhesion and release. The system is versatile, inexpensive, reproducibile, and also suitable for studies of the effects of pharmacologic agents and other aspects of platelet-artificial surface interaction.

Anticoagulants↗
PubMed1977

Isolation and comparison of ribothymidine-lacking tRNAs of fetal, newborn and adult bovine tissues.

Although ribothymidine (rT) is the most common methylated nucleoside in tRNA, a wide variety of bovine tissues have now been found to contain a class of tRNAs which totally lack rT and have an unmodified uridine in its place. The tissues studied include bovine brain, kidney, liver, thymus and testicles from adult, newborn and fetal stages. The class of tRNA was detected by its ability to be methylated with Escherichia coli rT-forming uracil methylase with radioactive S-adenosyl-L-methionine as the methyl donor. In each case rT was shown to account for at least 95% of the methylated products produced. In vitro methylated tRNA populations were compared by fractionation of double-labeled tRNAs on RPC-5 columns. Three major methyl-accepting tRNA peaks were found for all mammalian tissues studied. The level of methyl acceptance in these peaks was found to vary considerably between tRNAs of different tissues. A major difference in the methyl-accepting tRNA populations of bovine liver and calf thymus was observed. Little similarity was found in the rT-lacking class of tRNAs of bovine liver and wheat germ. Three members of the rT-lacking class of bovine liver tRNA were isolated and found to be two species of valine tRNA and one species of threonine tRNA. All three tRNA's completely lacked rT and could be quantitatively methylated with E. coli uracil methylase.

Aging↗
PubMed1977

Sleep patterns in the "locked-in" syndrome.

Sleep patterns in two chronically "locked-in" patients were studied. The first patient had sleep activity similar to other quadriparetic patients with reduced physical activity. The second patient experienced no REM sleep and only short bursts of non-REM sleep. Clinical evidence suggested extension of his lesion dorsally into the pontine tegmentum. This correlates well with experimental evidence indicating that structures in the tegmental area are essential for normal sleep.

Electroencephalography↗
PubMed1976

Identification of the milk fat globule membrane proteins. I. Isolation and partial characterization of glycoprotein B.

The salt soluble proteins from the fat globule membrane of cow's milk were resolved into three fractions by Sephadex column chromatography in sodium dodecyl sulfate. One of the fractions, termed glycoprotein B, was purified by rechromatography to essentially one band on sodium dodecyl sulfate gel electrophoresis. It was found to contain 14% carbohydrate including sialic acid, mannose, galactose, glucose, glucosamine and galactosamine. The amino acid composition of glycoprotein B was determined; it has amino terminal serine and carboxyl terminal leucine. The molecular weight of this glycoprotein as estimated by sodium dodecyl sulfate gel electrophoresis is 49 500.

Amino Acids↗
PubMed1976

A comparison of the bronchodilator activity of (+/-) 11-deoxy prostaglandin E1 with its 15-methyl analogue, (doxaprost).

The bronchodilator activity of (+/-) 11-deoxy prostaglandin E1 was compared to the activity of its (+/-) 15-methyl analogue, (doxaprost). Both compounds inhibited histamine-induced bronchoconstriction in the anesthetized guinea pig where changes in tracheal pressure were measured. Doxaprost was 73 and 32 times more potent that (+/-) 11-deoxy PGE1 by the aerosol and i.v. routes, respectively. Doxaprost also demonstrated a longer duration of effect. Both compounds decreased pulmonary resistance in the 5HT tonal cat. There was no difference in the potency of the two compounds. However, doxaprost had a longer duration of effect. Both compounds caused a fall in mean arterial blood pressure after i.v. administration in the guinea pig but not after aerosol administration in the guinea pig and cat. Both compounds caused relaxation of the isolated guinea pig tracheal strip when tone was induced with carbachol. There was no difference in the potency of the two compounds. The increased activity in vivo but not in vitro of the 15-methyl analogue doxaprost is consistent with a lack of enzyme inactivation.

Animals↗
PubMed1976

Peptides readily penetrate the blood-brain barrier: uptake of peptides by synaptosomes is passive.

The intracarotid artery quick injection technique of Oldendorf was utilized to determine the Brain Uptake Index (BUI) of radio-labeled peptides in comparison with 3H2O or 14C-antipyrine as counterlabels. The normalized BUI values for 3H-MIF-I, 3H-alpha-MSH and 14C-AVP were 13.7, 9.6 and 13.0 respectively at 15 sec after injection consistent with their having readily penetrated the blood-brain barrier. The BUI values were similar, though somewhat increased, at 10 min postinjection consistent with their ready exit across the blood-brain barrier. At 15 sec after injection 0.5+/-0.1%/g brain of the originally injected peptide label was recovered; and 0.1+/-0.2%/g brain was recovered after 10 min. The label was distributed uniformly in the major brain regions at both times. However, the percentage of the originally injected label/g of pineal and pituitary gland tissue was 10-20 X increased as compared with the major brain regions as would be expected by their location outside the blood-brain barrier. The in vitro uptake of the radio-labeled peptides by synaptosomes prepared from the whole brain and the major brain regions was passive; it was not temperature dependent, nor was it Na+ dependent. However, the binding of the three peptides by the synaptosomes varied considerably: AVP greater than MSH greater MIF: 50 greater than 5 greater 1. The penetratin of the blood-brain barrier by the three peptides is consistent with their having CNS effects.

Animals↗
PubMed1976

Self-disclosure: an attributional perspective.

This experiment examined the effect of timing of an intimate disclosure and assignment of responsibility for the event disclosed on interpersonal attraction. Subjects were induced to interact with a confederate who in all cases revealed something quite personal about himself. The disclosure occurred either early or near the end of a 10-minute conversation. The confederate accepted responsibility for the event disclosed, did not mention responsibility, or assigned responsibility to external factors. Negative traits were assigned to the early disclosure, and he was liked significantly less than the late discloser. The results are explained in terms of differential attributions made to early and late disclosures. The results for the assignment of responsibility variable were surprising: The confederate who accepted responsibility for the event disclosed elicited more negative reactions than the confederate who blamed other factors or who did not mention responsibility. Some possible reasons for this unexpected finding are discussed.

Humans↗
PubMed1976

The role of bound calcium in supersensitivity induced by cocaine.

1 Noradrenaline caused a small contraction of the cat isolated spleen strip bathed in a calcium-free solution; this contraction was greatly potentiated by cocaine. This potentiation was also present in isolated spleen strips where noradrenaline stores were depleted by reserpine. The maximum response of the spleen strip to noradrenaline in the absence of extracellular calcium was also increased by cocaine. 2 The disodium salt of ethylenediaminetetraacetic acid (Na-EDTA) but not Ca-EDTA antagonized the potentiation of the response to noradrenaline by cocaine in a calcium-free solution, and greatly reduced the magnitude of subsequent responses to noradrenaline and cocaine. 3 Strontium caused equivalent contractions of normal and reserpine-treated spleen strips bathed in a calcium-free solution. These responses were potentiated by cocaine. 4 Histamine caused a small contraction of the isolated spleen strip bathed in a Ca-free solution. Cocaine failed to potentiate these very small histamine contractions, but did potentiate the contraction of these same strips in response to noradrenaline. 5 It is concluded that the potentiation of the response of the isolated spleen strip to noradrenaline by cocaine in the absence of extracellular calcium is due to a mechanism other than decreased neuronal uptake of noradrenaline. It is suggested that cocaine makes a bound store of calcium more available to promote contraction of the spleen strip by noradrenaline.

Animals↗
PubMed1976

Transcription of the genome of adenovirus type 12. III. Maps of stable RNA from productively infected human cells and abortively infected and transformed hamster cells.

The adenovirus type 12-specific mRNA and the stable nuclear RNA from productively infected KB cells, early postinfection, from abortively infected BHK-21 cells, and from the adenovirus type 12-transformed hamster lines T637 and HA12/7 have been mapped on the genome of adenovirus type 12. The intact separated heavy (H) and light (L) strands of adenovirus type 12 DNA have been used to determine the extent of complementarity of the mRNA or nuclear RNA from different cell lines to each of the strands. More precise map positions have been obtained by the use of the H and L complements of the fragments of adenovirus type 12 DNA which were produced with the EcoRI and BamHI restriction endonucleases. The results of the mapping experiments demonstrate that the mRNA's isolated early from productively and abortively infected and from two lines of transformed cells are derived from the same or similar regions of the adenovirus type 12 genome. The map positions on the adenovirus type 12 genome for the mRNA from the cell lines as indicated correspond to regions located approximately between 0 and 0.1 and 0.74 and 0.88 fractional length units on the L strand and to regions between 0.63 and 0.74 and 0.89 and 1.0 fractional length units on the H strand. The HA12/7 line lacks mRNA complementary to the region between 0.74 and 0.88 fractional length units on the L strand. Similar data are found for the nuclear RNA, except that the regions transcribed are more extensive than those observed in mRNA. The polarity of the H strand has its 3'-end on the right terminus in the EcoRI A fragment, and the L strand has its 3'-end on the left terminus in the EcoRI C fragment. Thus, the H strand is transcribed from right to left (1 = leftward strand); and the L strand is transcribed from left to right (r = rightward strand). The designations H and L refer to the relative heavy and light densities of the two strands in polyuridylic-polyguanylic acid-CsCl density gradients. The EcoRI C-H and D-H complements have been shown to be part of the intact L strand; thus, there is a "reversal in heaviness" on the left terminus of the viral DNA.

Adenoviruses, Human↗
PubMed1976

REM sleep and adaptation of psychiatric patients: an application of sleep studies.

The authors used sleep laboratory data to predict responses to psychiatric treatment. The predictions were based on the assumptions that REM latency reflects the need for dreaming and therefore the need for adaptation and that REM time reflects the capacity for the adaptive work associated with REM sleep. Dream recall and dream content were considered indicators of psychological mindedness and the patient's current conflicts. With this material, statistically significant predictions of such outcomes as good response to psychotherapy, elopement, or need for medication were made. The results of this study support the hypothesis that REM sleep is involved in adaptation.

Adaptation, Psychological↗
PubMed1976

Amino terminal sequence and location of phosphate groups of the major human casein.

The amino acid sequence of the first 28 residues of the major human casein was determined. This protein in multiphosphorylated forms (0 to 5 phosphorous per molecule) was compared to cow beta-casein which is similar in composition but phosphorylated at a constant level. After sequencing the phosphate-free human casein, phosphorylated seryl and threonyl residues were located in three of the other phosphorylated forms by examining the aqueous layer of the phenylthiohydantoin conversion step during automatic liquid phase sequencing. Phosphate groups on specific seryl/threonyl residues suggest a biosynthetic mechanism involving stepwise phosphorylation or dephosphorylation.

Amino Acid Sequence↗
PubMed1976

Electromyography before and after surgery for hip deformity in children with cerebral palsy. A comparison of clinical and electromyographic findings.

Twenty-three ambulatory children with spastic diplegic cerebral palsy were evaluated clinically and by electromyography before and after hip-muscle surgery. The stretch tests originally designed to distinguish specific muscle tightness and spasticity were found to be non-specific when tested by electromyography. Ambulatory electromyograms using needle electrodes and telemetry generally showed decreased activity in the released muscles and, on occasion, changes in activity in muscles not operated on. These unanticipated changes after release may explain some of the unpredictability of results of such procedures in cerebral palsy.

Adolescent↗