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Biomedical subjects

R J Allen

Publications and source records attributed to R J Allen.

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

Ozone production from photocopying machines.

Ten photocopying machines of different makes and models were tested for ozone emissions. All but one produced detectable amounts. Concentrations at operator's breathing zone varied from less than 4 to 300 micrograms/m3, which corresponded to emission rates of less than 1 to 54 micrograms/copy. Servicing reduced emissions to less than 1.4 micrograms/copy, but preservicing levels were retained after several weeks of operation.

Air Pollutants↗
PubMed1980

The effect of purified lipopolysaccharide on the bactericidal reaction of human serum complement.

Escherichia coli ML308 225 was killed and lysed by human serum. Bacterial sensitivity to serum was maximal for organisms in the early-exponential phase of batch culture and declined as growth proceeded. Bacterial killing was dependent upon the complete complement sequence and the subsequent action of serum lysozyme caused bacteriolysis. Purified lipopolysaccharide from this organism bound to serum-sensitive bacteria and inhibited the bactericidal reaction.

Blood Bactericidal Activity↗
PubMed1979

Biosynthesis and turnover of outer-membrane proteins in Escherichia coli ML308-225.

Isolated outer membranes and outer-membrane extracts from Escherichia coli ML308-225 in the early-exponential growth phase contain more protein than do corresponding preparations from late-exponential- or stationary-phase bacteria. Isotope-dilution experiments show that this is due to a loss of protein from the membrane during the exponential growth phase. Inhibition of bacterial growth and protein synthesis stabilizes the outer-membrane-protein concentration. Protein synthesis in the absence of bacterial growth results in higher concentrations of protein in the outer membrane.

Bacterial Proteins↗
PubMed1979

Computed tomography in oculocraniosomatic disease (Kearns-Sayre syndrome).

Computed tomography (CT) in patients with oculocraniosomatic disease (OCSD) or Kearns-Sayre syndrome has not been previously reported to the authors' knowledge. CT scans were performed in 6 children and 3 adults with OCSD. Abnormalities in children included: intracranial calcifications (4 patients); white matter disease (3 patients); cerebellar hypoplasia (1 patient); and scattered areas of decreased density in the cerebellar hemispheres, mesencephalon, and thalamus (1 patient). CT scans were normal in all adults. OCSD should be considered in the differential diagnosis in patients with intracranial calcification and white matter disease.

Adolescent↗
PubMed1978

Characterization of potential indoor sources of ozone.

Ozone emission factors were developed for domestic electrostatic air cleaners and photocopying machines. The air cleaners had emission rates from 0-546 microgram/min. These rates will ordinarily not produce air concentrations which are greater than 60 microgram/m3 (0.030 ppm) above background. The emission rate for photocopying machines varied from 48-158 microgram/copy. In small, poorly ventilated rooms these emission rates were sufficient to produce incremental steady state ozone concentrations up to 396 microgram/m3 (0.202 ppm). Recent copying machine maintenance was found to reduce ozone production to less than the detectable level, 4 microgram/m3 (0.002 ppm).

Air↗
PubMed1977

Fisher's syndrome in children.

Fisher's syndrome is characterized by ophthalmoplegia, ataxia, and areflexia. The clinical course is usually benign with complete recovery. We report a case that developed following a bee sting and review the literature of Fisher's syndrome in children. Its history, pathogenesis, and relationship to Guillain-Barré syndrome are also discussed.

Animals↗
PubMed1976

Micellar catalysis of the alkylation of mercuric ions by alkyl cobalt(III) complexes.

Anionic micelles of sodium lauryl sulfate, NaLS, catalyze the monoalkylation of Hg2+ in dilute acid by alkyl aquobis-(dimethyl glyoximato) cobalt (III), RCo(DH)2(H2O) degrees and the related propane derivatives RCo(DOH) DOpn (H2O)+, where R = Me, Et, n-C5H11. Nonionic micelles of Igepal do not catalyze the reaction. In the absence of micelles RCo(DH)2(H2O) degrees is considerably more reactive than RCo(DOH)DOpn(H2O)+, but this higher reactivity is offset in part by its higher basicity. Anionic micelles markedly increase the basicity of RCo(DOH)DOpn(H2O)+ and slightly increase that of RCo(DH)2(H2O) degrees. For reactions of the unprotonated Co(III) complexes the maximum rate enhancements by micelles of NaLS are: R = Me, 19(131); Et, 58 (65); n-C5H11, 46 (32). (The values in parentheses are for RCo(DOH)DOpn(H2O)+.)

Alkylation↗
PubMed1976

Micellar effects upon the reaction of cobalt complexes with alkyl halides.

The reactions of the cobalozime Co (DH)-2 and the related Co(DOH)DOpn0 are strongly catalyzed by cationic micelles of cetyltrimethylammonium bromide (CTABr). The rate enhancements for the cobaloxime reaction and for that of Co (DOH)DOpn0 (in parentheses) are: EtBr approximately 1 (8.5); n-C5H11Cl, 220 (200); ClCH2CO-2, 420 (173); ClCH2CH2CO-2, 373. Anionic micelles of sodium lauryl sulfate inhibit the reaction of Co(DOH)DOpn0 with ClCH2CO-2, but do not affect that with n-C5H11Cl. The reactions of Co(DOH)DOpn0, like those of the cobaloxime are SN2 displacements and in the absence of surfactant in MeOH n-PrBr is more reactive than iso-PrBr.

Binding Sites↗