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Biomedical subjects

W E Johnson

Publications and source records attributed to W E Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Effects of general central nervous system depressants with and without calcium ionophore A23187 of rat cerebellar cyclic guanosine 3',5'-monophosphate.

Rat cerebellar cyclic guanosine 3',5'-monophosphate (cGMP) concentrations were determined by radioimmune methods after sacrifice with focused microwave fixation in animals pretreated with either ethanol, pentobarbital, or diethyl ether, either alone or in combination with the calcium ionophore A23187. Both pentobarbital sodium and diethyl ether produced a dose-dependent depression of cerebellar cGMP. When A23187 was administered alone, significant increases of cerebellar levels of cGMP were observed. The administration of A23187 to animals acutely intoxicated with ethanol, pentobarbital, or diethyl ether resulted in significant depression of cerebellar cGMP levels.

Animals↗
PubMed1979

Duplication 6q syndrome.

Duplication (partial trisomy) of the long arm of chromosome 6 has been described in 5 children [Robertson et al, 1975, Chen et al, 1976, Clark, 1977]. We wish to report here an additional case due to a familial translocation in which the proband's karyotype is 46,XX,der(3),rcp(3;6)(p25;q21)mat. The phenotypes of the 6 children with duplication 6q are strikingly similar. Each child has duplication involving approximately the distal 1/3 to 1/2 of the long arm of chromosome 6. Distinctive features present in all 6 children include microcephaly, acrocephaly, prominent forehead, flat facial profile, depressed nasal bridge, flat malar areas, "carp" mouth, micrognathia and mental retardation. The phenotype of the duplication 6q syndrome is distinctive enough to be clinically recognizable.

Abnormalities, Multiple↗
PubMed1979

Effect of calcium concentration, isoproterenol, and McN-2165 on fetal rat heart rate and cyclic AMP level.

The fetal rat heart in organ culture was used to study the interaction of calcium with the cardioactive agents. McN-2165 is an agent that produces negative chronotropism and elevation in cyclic AMP levels in this preparation. A concentration of 2.76 mM calcium ion antagonized the negative chronotropic action and prevented the cyclic AMP elevation produced by this agent. Positive chronotropic actions of isoproterenol were prevented by decreasing the calcium level below 1.84 mM.

Animals↗
PubMed1978

Negative chronotropic action of cyclic AMP on the fetal rat heart in organ culture.

Dibutyryl cyclic AMP and cyclic AMP in a DMSO medium were administered to the fetal rat heart in organ culture. Changes in heart rate were observed. Dibutyryl cyclic AMP in concentrations of 5 X 10(-5) M and 1 X 10(-4) M produced significant negative chronotropism. At a concentration of 1 X 10(-3) M, cyclic AMP in a 3% or 0.5% DMSO medium produced significant negative chronotropism. These data were compared with other studies. The negative chronotropic action of cyclic AMP and its dibutyryl derivative are evidence against the involvement of cyclic AMP in positive cardiac chronotropism.

Animals↗
PubMed1977

Gm and Km(Inv) frequencies in two Roumanian populations.

Serum samples from 170 unrelated individuals from the Suceava District of Roumania and from 199 unrelated individuals from Bucharest, Roumania were tested fro Gm(1,2,3,5,6,13,14,17,21) and Km(1)[Inv(1)]. Selected samples were also tested for Gm(15) and Gm(16). The frequencies of the three common Caucasoid haplotypes, Gm3,5,13,14, Gm1,17,21, and Gm1,2,17,21 in these two populations were found to be similar to those in neighboring Slavic states and Hungary. Racial admixture was evidenced by the presence of the Gm1,13,15,16,17 and Gm1,3,5,13,14 haplotypes, which are primarily Mongoloid, and the Gm1,5,13,14,17 haplotype which is primarily Negroid. Comparisons of these data with those from earlier studies of populations from Central Europe indicate that the frequency of the Gm3,5,13,14 haplotype within this region is high and essentially uniform. Published data for several blood group systems also indicate essentially uniform distributions of frequencies in this region. It is suggested that this region may be the center of a cline that radiates from it.

Asian People↗
PubMed1977

Chronotropic and cyclic adenosine monophosphate response of fetal rat heart in organ culture to isoproterenol, quinidine, and a dysrhythmogenic agent.

The fetal rat heart in organ culture was used to investigate rate chanes by various cardioactive agents. Concomitantly, the effect of these pharmacologically induced rate changes on steady-state cyclic adenosine monophosphate levels was determined. Isoproterenol increased the fetal rat heart rate and cyclic adenosine monophosphate in a concentration-related fashion. Quinidine produced a concentration-related decrease in heart rate and no change in cyclic adenosine monophosphate level. The dysrhythmogenic agent produced concentration-related negative chronotropism in the fetal rat heart preparation and significant elevations in cyclic adenosine monophosphate at concentrations without chronotropic action. No correlation between chronotropic effect of a drug and cyclic adenosine monophosphate levels was observed.

Animals↗
PubMed1975

Allozymic and chromosomal similarity in two Drosophila species.

D. setosimentum and ochrobasis are a pair of very close, partly sympatric species endemic to Hawaii island. Males of the two species differ strikingly in wing-pattern and there are altitudinal and breeding-site differences. Similarity indices have been calculated for both chromosomal (C) ald allozymic (A) variants. Within the main populations of each species both kinds of data give coefficients above 0.98. Interspecific comparison of the main populations shows 0.66 (C) and 0.79 (A). An isolated population of ochrobasis from Kohala Volcano (Ohu), when compared with setosimentum, shows 0.68 (C) and 0.98 (A). Chromosomes are thus much more sensitive than allozymes in distinguishing these species; the same is true in the case of D. silvestris and heteroneura from the same forests. These morphologically distinct species, when compared, show 0.96 (A). All four species appear to be very new in the historical sense. In one area, about 2% of wild-caught D. setosimentum/ochrobasis are interspecific hybrids although adequate samples indicate that the separate gene pools have not broken down. The specific names should be retained but the two entities are perhaps best described as quite advanced semispecies in which reproductive isolation in nature is now nearly complete.

Animals↗