Biomedical subjects
J Johnson
Publications and source records attributed to J Johnson.
The relationship of oestradiol receptor (ER) and histological tumour differentiation with prognosis in human primary breast carcinoma.
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The nurse and cancer patient education.
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The effect of cigarette smoke on the permeability of guinea pig airways.
The epithelium lining the conducting airways restricts the movement of inhaled foreign materials into the interstitial and circulatory space. In the present study, we have investigated the effects of graded doses of inhaled whole cigarette smoke on this function by measuring the rate of movement of horseradish peroxidase (HRP) from the airways lumen across the tracheal epithelium into blood, by assessing the penetration of HRP into tracheal epithelium using transmission electron microscopy, and by examining the morphology of tracheal epithelial tight junctions using the freeze-fracture technique. These studies showed that 5, 20, and 100 puffs of whole smoke increased penetration of HRP from the tracheal lumen into blood in a dose-dependent fashion. Transmission electron microscopy showed that HRP penetrated the tracheal epithelium only in the 100-puff exposure group while the freeze-fracture studies showed progressive disruption of epithelial tight junction beginning with a 100-puff exposure and becoming more extensive after the 200-puff exposure. We conclude that inhaled cigarette smoke damages the mucosal barrier and causes increased permeability to HRP by disrupting the intercellular tight junctions and that measuring the appearance of HRP in blood is more sensitive than electron microscopy in assessing this damage.
Specific effects of nalidixic acid on mitochondrial gene expression in Saccharomyces cerevisiae.
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Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G.
Treatment of turkey liver fructose-1,6--bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was perfomed in the presence of substrate.
A comparison of xenon-133 clearance with electromagnetic flowmeters and an indicator dilution method for the measurement of liver blood flow.
Measurement of liver blood flow has been carried out by three different methods in 14 dogs to assess the accuracy of xenon-133 clearance following portal vein injection. Electromagnetic flowmetry with flow probes on the hepatic artery and portal vein resulted in a mean value of 121.9 +/- 39.3 ml min-1 100 g-1. An indicator dilution study utilizing chromium-51-labelled red cells gave a mean value of 119.4 +/- 31.4 ml min-1 100 g-1 and the xenon-133 clearance following portal vein injection, 120.3 +/- 33.8 ml min-1 100 g-1. One-way analysis of variance showed no statistically significant variation between these three groups. There was a close correlation between xenon-133 clearance and electromagnetic flowmetry and between xenon-133 clearance and the indicator dilution technique. These data suggest that xenon-133 clearance following portal vein injection gives an accurate assessment of liver blood flow and this technique (as well as direct parenchymal injection) can be adapted for clinical use.
Short term metronidazole therapy contrasted with povidone-iodine spray in the prevention of wound infection after appendicectomy.
In a prospective, randomized trial metronidazole was found to be significantly better than povidone-iodine in reducing the incidence of wound infection after appendicectomy (P less than 0.005). The metronidazole was given as a established 7-day course. Over 65 per cent of the wound infections presented after the patients had been discharged from hospital.
Characterization of the WIDR: a human colon carcinoma cell line.
We describe the establishment and characterization of WiDr, a cell line derived from a human colon carcinoma. It produces carcinoembryonic antigen in culture, and has a doubling time of 15 hr with plating efficiency of 51%. The HLA antigenic profile and the allozyme genetic signature (composed of eight gene-enzyme systems) of WiDr cells are different from those of HeLa cells. Furthermore, WiDr cells possess three marker chromosomes, again distinct from the HeLa marker chromosomes. Finally, it is highly tumorigenic in four different xenogeneic animal models. Based on these studies, WiDr represents a useful model cell line for tumor cell biology investigations.
New arterial cannulation techniques in cadaver kidney preservation.
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Comparative effects of naproxen and aspirin on fever in children.
The antipyretic effect of single doses of naproxen, 2.5 mg/kg or 7.5 mg/kg, was compared to that of aspirin, 15 mg/kg, and of a placebo in a double-blind study. Febrile children, hospitalized overnight, were randomly assigned to one of the treatment or placebo groups, and their temperatures were recorded hourly. Naproxen, 7.5 mg/kg, was at least as effective as aspirin in onset of action and reduction of fever, and had a longer duration of action. Each of the three treatments had a significant effect as compared to that of the placebo. There was no difference in the total incidence of side effects among the four groups, but mild gastrointestinal complaints were more common among the patients in the high-dose naproxen group, whereas CNS complaints were more prevalent among the patients in the placebo group.
Folate antagonists. 15. 2,3-Diamino-6-(2-naphthylsulfonyl)quinazoline and related 2,4-diamino-6-[(phenyl and naphthyl)sulfinyl and sulfonyl]quinazolines, a potent new class of antimetabolites with phenomenal antimalarial activity.
Oxidation of an array of 2,4-diamino-6-(arylthio)quinazolines provided the corresponding arylsulfinyl and arylsulfonyl analogues. A variety of these nonclassical analogues of methotrexate exhibited suppressive antimalarial activity superior to that of the parent thioquinazolines against drug-sensitive lines of Plasmodium berghei in mice and P. gallinaceum in chicks, and several displayed potent prophylactic activity against P. gallinaceum. The sulfinyl- and sulfonylquinazolines also retained antimalarial effects against chloroquine-, cycloguanil-, and DDS-resistant lines of P. berghei in mice and against chloroquine- and pyrimethamine-resistant strains of P. falciparum in owl monkeys. Coadministration of one of the most active of these compounds, 2,4-diamino-6-(2-naphthylsulfonyl)-quinazoline (35), with sulfadiazine to monkeys infected with P. falciparum of P. vivax led to greatly enhanced activity and prevented the development of quinazoline resistance.
Structural bases of the inhibitory effects of hemoglobin F and hemoglobin A2 on the polymerization of hemoglobin S.
We have previously found that the inhibitory effect of hemoglobin F (Hb F) on the polymerization of Hb S proceeds via the formation of asymmetrical hybrid tetramers of the type alpha2betasgamma. Examination of the gelling properties of binary mixtures of Hb S and several Hb variants now shows that, among the gamma chain amino acid residues that differ from those of the beta chain, residues gamma80 (EF4) and gamma87 (F3) are at least partly responsible for this inhibition. Furthermore, we find that mixing Hb A2(alpha2delta2) with Hb S strongly inhibits gelling to an extent similar to that seen with Hb S/Hb F mixtures; this inhibition is attributable to amino acid differences between the delta and beta chain sequences at positions delta22 (B4) and delta87 (F3). Therefore, residues 22, 80, and 87 of the beta chain appear to be involved in intermolecular contact sites that stabilize the deoxy Hb S polymers.
Effects of morphine on ventilatory response to exercise.
The effects of analgesic doses of morphine on ventilation, arterial blood gas tensions, chemical control of breathing, and the ventilatory response to exercise were studied in six normal subjects. After administration of 0.2 mg/kg morphine, resting ventilation decreased primarily because of a reduction of tidal volume. Ventilatory responses to carbon dioxide and hypoxia were significantly reduced to one-half and one-third of control, respectively. Ventilatory responses at any given level of exercise were significantly reduced after morphine. However, since oxygen consumption during exercise was similarly reduced after morphine, the relationship between ventilation and metabolic rate during steady-state exercise was not altered by the drug. In addition, morphine prolonged the attainment of steady-state ventilation in four of the six subjects, similar to that reported for chemodenervated subjects. The findings suggest that blunting of chemoreception for hypoxia and hypercapnia has no effect upon the link between metabolic rate and ventilation during steady-state exercise, but the hypoxia chemoreflex may be involved in determining the dynamic characteristics of the response.
Cimetidine and psychiatric complications.
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Havelock Ellis and his 'Studies in the psychology of sex'.
The life of Havelock Ellis is described; his personality and life experiences are related to the writing of his major work. Important sections of the 'Studies' are summarized and their relevance to contemporary sexology is emphasized.
Practical immunization of chickens against coccidiosis using an attenuated strain of Eimeria tenella.
Three floor-pen trials were conducted to compare two attenuated strains of Eimeria tenella (Wis-F-96 and Wis-F-125) with the strain of E. tenella used in a commercial planned immunization program (Coccivac). Broiler cockerels were started in floor pens on new pine shavings litter. Immunizing oocysts were administered in the drinking water during the first week with total dose per bird of 175 oocysts of the control strain (Coccivac); 175, 350, or 700 oocysts of the Wis-F-125; 350 oocysts of Wis-F-96; or no oocysts (non-seeded control). The control strain was more pathogenic than the Wis-F-125 or the Wis-F-96 strains as indicated by significantly higher lesion scores 17 days after initial exposure and by loss of two birds in the control strain exposed groups. Low lesion scores and no deaths due to coccidiosis characterized the use of the Wis-F-125 strain. Flock immunity, as determined by immunity challenge, was equivalent between the control strain and the higher dosages of Wis-F-125. The Wis-F-96 strain did not adequately immunize chickens in these experiments.