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Biomedical subjects

S Johnson

Publications and source records attributed to S Johnson.

At least 487 records · Page 27Linked to original sources
PubMed1984

Improved survival of newborns receiving leukocyte transfusions for sepsis.

To determine the role of polymorphonuclear (PMN) leukocyte transfusions in neonates with sepsis, 23 consecutive newborns were prospectively randomly selected during an 18-month period in a treatment plan to receive polymorphonuclear leukocyte transfusions with supportive care or supportive care alone. Thirteen neonates received transfusions every 12 hours for a total of five transfusions. Each transfusion consisting of 15 mL/kg of polymorphonuclear leukocytes was subjected to 1,500 rads of radiation. The polymorphonuclear leukocytes were obtained by continuous-flow centrifugation leukapheresis and contained 0.5 to 1.0 X 10(9) granulocytes per 15 mL with less than 10% lymphocytes. Pretreatment demographic, clinical, and laboratory variables that were found to be insignificant in prognosis between newborns who received transfusions and newborns who did not receive transfusions included weight, gestational and postnatal age, hypoxia, acidosis, hypotension, initial absolute granulocyte count (AGC), initial levels of immunoglobulins (IgA, IgG, and IgM), and total hemolytic complement. Positive findings on blood cultures were obtained in 14/23 patients and seven were randomly selected for each treatment group. Absolute granulocyte counts were less than 1,500/microL in 13 patients but tibial bone marrow examinations revealed that the neutrophil supply pool was depleted in only three patients. The survival was significantly greater in the treatment group (13/13, 100%) compared with the group that did not receive transfusions (6/10, 60%, P less than .02).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1984

Studies on the metabolism of D-penicillamine and its interaction with probenecid in cystinuria and rheumatoid arthritis.

Four patients with recurrent cystine stones and 5 with rheumatoid arthritis (RA) were studied. After a single dose of D-penicillamine to cystinuric patients, cystine excretion decreased considerably. Cysteine-penicillamine mixed disulfide (CSSP) and penicillamine disulfide (PSSP) metabolites appeared within 1-2 h (CSSP/PSSP approximately equal to 4.8-8.6). In RA, cystine excretion remained negligible (CSSP/PSSP approximately equal to 1.4-2.9). With daily D-penicillamine in RA (CSSP/PSSP ratios were usually greater than 7 in those with favorable clinical response. CSSP/PSSP ratios may help to predict prognosis and adjust penicillamine dosage. Coadministration of probenecid is contraindicated in hyperuricemic cystinuric patients because of increased cystine and decreased CSSP and PSSP excretion.

Arthritis, Rheumatoid↗
PubMed1984

Ventilators.

Explore the source record for details and available documents.

Adult↗
PubMed1983

Mechanism of action of the endonuclease associated with the alpha beta and beta beta forms of avian RNA tumor virus reverse transcriptase.

Preparations of the alphabeta and the betabeta forms of reverse transcriptase from the Prague C strain of Rous sarcoma virus grown in chicken embryo fibroblasts, the alphabeta and the betabeta forms of the enzyme from the B77 strain of Rous sarcoma virus grown in duck embryo fibroblasts, and the alphabeta form of reverse transcriptase from avian myeloblastosis virus have been analyzed. All these enzyme preparations contain a Mn(2+) -activated endonuclease activity. The betabeta form of enzyme, in addition, contains a Mg(2+) -dependent endonuclease. Such an activity is barely detectable in the alphabeta form of enzymes. The endonuclease associated with reverse transcriptase introduces single- and double-strand breaks containing 3' OH and 5' P termini into RF I DNA. The conversion of RF I DNA to RF III DNA is more readily catalyzed by the betabeta form of reverse transcriptase. In contrast to a recently published report by Hizi et al. (J. Virol 41:974-981, 1982), we have failed to detect the conversion of RF I DNA to covalently closed relaxed circles (RF IV DNA) by any of the alphabeta form of enzymes tested. RF IV DNA was not produced by the betabeta form of reverse transcriptase either. We conclude that topoisomerization is not an intrinsic activity of reverse transcriptase. Although the conversion of RF I DNA to RF II DNA was found to be rapid, the endonuclease associated with reverse transcriptase acted slowly on RF II, RF III, and RF IV DNAs. Circular and linear single-stranded DNAs were also susceptible to cleavage by the endonuclease at a rate comparable to nicking of RF I DNA. This pattern of activity suggests that the endonuclease cleaves the RF I DNA in the single-stranded regions of the DNA induced by its supercoiling. The preference of the alphabeta and the betabeta forms of the endonuclease for viral DNA was tested with Rous-associated virus type 2 and Rous sarcoma virus transformation-defective Schmidt-Ruppin B strain DNA molecularly cloned in plasmid pBR322 and M13 DNA vectors, respectively. The rate of nicking of RF I DNA containing viral DNA or partial sequences of viral DNA with one or two tandem long terminal repeats was the same as when these sequences were not present in the host vectors. A similar lack of preference was observed with single-stranded M13 DNAs.

Avian Leukosis Virus↗
PubMed1983

Plasmid profile, serogrouping, and auxotyping of Neisseria gonorrhoeae isolates from Africa.

The plasmid patterns of 90 isolates of Neisseria gonorrhoeae (including 39 penicillinase-producing strains) originating from various countries in Africa were determined. Serogrouping by coagglutination and auxotyping were used to characterise the isolates. The 4.4-megadalton plasmid was present in seven isolates out of 39 penicillinase-producing strains, two of which occurred with a conjugative 24.5-megadalton plasmid. The African strains were predominantly serogroup WI and wild type. Arginine-dependent isolates were as common as proline-dependent types.

Africa↗
PubMed1983

Epidemiological characterisation of Neisseria gonorrhoeae isolates from the Far East.

One hundred strains of Neisseria gonorrhoeae (including 30 penicillinase producing (PPNG) strains) originating from Korea were characterised by plasmid analysis, auxotyping, and serogrouping. Eighty per cent of the isolates possessed the conjugative 24.5 megadalton (Mdal) plasmid. A novel 7.8 Mdal plasmid was present in four isolates (one PPNG and three non-PPNG strains). Seventy five per cent of all the strains tested were wild type and belonged to serogroup WII, while 20% were proline requiring and belonged to serogroup WII. Two of the remaining strains were tyrosine auxotrophs, while another strain was arginine requiring; these three strains carried the conjugative plasmid and belonged to serogroup WII.

Gonorrhea↗
PubMed1983

In vitro activity of augmentin against pathogenic bacteria and its comparison with other antibiotics.

190 isolates from clinical specimens were tested in vitro to determine their susceptibility pattern against augmentin. Of the 132 strains of Enterobacteriaceae tested, 109 (82.6%) were susceptible. 41 (93.2%) of the 44 gram-positive bacteria tested were also susceptible to augmentin. Strains of Pseudomonas aeruginosa and Serratia marcescens were resistant to augmentin. However, augmentin showed increased activity against Escherichia coli, and Staphylococcus aureus when compared with ampicillin.

Amoxicillin↗
PubMed1983

Common ALL with pre-B-cell features showing (8;14) and (14;18) chromosome translocations.

A 21-yr-old man presented with inguinal lymphadenopathy and splenomegaly. The peripheral blood showed a high blast cell count. The morphological and immunologic features of the blast cells were consistent with the diagnosis of common acute lymphoblastic leukemia (ALL) with 15% pre-B-cells. Banded karyotype analysis of the blood and the marrow cells, using the technique of methotrexate synchronization, revealed the presence of (8;14) and (14;18) chromosome translocations, a finding that has not been previously documented. The significance of these findings is discussed.

Adult↗
PubMed1983

Metabolic cost of extremely slow walking in cardiac patients: implications for exercise testing and training.

To assess metabolic cost of extremely slow walking, nine patients with coronary heart disease (means age, 56.1 yr) underwent multistage treadmill testing using standard open circuit calorimetry techniques. Heart rate, blood pressure, minute ventilation, and oxygen uptake in METS (1MET = 3.5 ml/kg/min) were determined at rest and at six submaximal work loads: 0.8, 1.0, 1.5, 2.0, 3.0 and 3.5mph, 0% grade. The oxygen uptake versus walking speed (0.8 to 3.5mph) relationship was y = 0.2064 (x)2 + 0.0180 (x) + 1.7260 (y = METS and x = speed in mph), r = 0.99. Results indicate that low-level exercise test protocols employing work loads between 0.8 and 2.0 mph impose similar metabolic and cardiac demands. Extremely slow walking approximates 2METS and may impose metabolic loads sufficient for exercise training in select patients with coronary heart disease.

Blood Pressure↗
PubMed1982

Biochemical and crystallographic data for phaseolin, the storage protein from Phaseolus vulgaris.

We have isolated and biochemically characterized a major seed protein from Phaseolus vulgaris (common garden green bean) that appears to be identical with a form of the storage protein of that plant seed known as phaseolin. We have further shown that it appears very similar in most properties to the storage protein from Canavalia ensiformis (jack bean) which we have solved to 3.0-A resolution using X-ray diffraction techniques. [McPherson, A., & Rich, A. (1973) J. Biochem. (Tokyo) 74, 155-160; McPherson, A., & Spencer, R. (1975) Arch. Biochem. Biophys. 169, 650-661; McPherson, A. (1980) J. Biol. Chem. 255, 10472-10480]. We have crystallized phaseolin and conducted a preliminary X-ray diffraction analysis on it as well. The data show the crystals to be of pseudo cubic space group P432, although the symmetry can be, strictly speaking, only P1. The unit cell has one trimeric molecule of 150 000 daltons in a unit cell of dimensions a = b = c = 66.6 and alpha = beta = gamma = 90 degrees. The crystals apparently possess some form of disorder that makes reconciliation of the unit cell contents with the observed crystallographic properties difficult, although they do diffract strongly to better than 2.8-A resolution. No evidence of twinning has been observed.

Amino Acids↗
PubMed1982

Hepatitis and haemophilia therapy in Australia.

243 Australian haemophiliacs have been studied retrospectively over 4 1/2 years to assess the effect of treatment products on liver function and to determine the frequency of hepatitis-B markers in these patients. Commercial blood products are not used in Australia, and the patients were treated with products of blood from unpaid donors screened for hepatitis B surface antigen. Cryoprecipitate was the major treatment product, and only small amounts of factor VIII and IX concentrates were used. Despite the use of blood products obtained from entirely voluntary blood donors and the frequent use of single-donor packs of cryoprecipitate, markers of viral hepatitis were common in these haemophiliacs. Antibody to hepatitis B surface antigen was detected in 63% of the patients, and there were 66 cases of non-A, non-B hepatitis during the study. 29 of these episodes persisted for longer than 6 months. 13 patients (5.4%) had hepatitis B during the study; 2 patients remained HBsAg-positive for longer than 6 months. Abnormal serum aminotransferase levels were found in 34% of the patients; in 8% of patients these abnormalities persisted for more than 6 months.

Adolescent↗
PubMed1982

The nature and treatment of giardiasis in parakeets.

The prevalence of giardiasis was studied in 77 parakeets from 4 widely varied sources and was found to be 66%. The infection appeared most common in young birds. Cysts and trophozoites were found in fecal samples and persisted in birds caged alone for up to 4 months, New infections appeared when infected and noninfected birds were caged together, Treatment with 200 ppm of dimetridazole in the drinking water was less effective than 3 oral doses given at the rate of 1.5 mg/30 g of body weight every 12 hours by stomach tube. Metronidazole therapy was not effective.

Animals↗