Search PubMed⌕ Search

Biomedical subjects

A J Johnson

Publications and source records attributed to A J Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1979

Transmission of Sarcocystis suihominis from humans to swine to nonhuman primates (Pan troglodytes, Macaca mulatta, Macaca irus).

Sporocysts of Sarcocystis suihominis obtained from human feces were used to infect swine. Heart, tongue, and skeletal muscle from experimentally infected and noninfected control swine were fed via stomach tube to nonhuman primates including chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), and cynomolgus monkeys (Macaca irus). All primates fed infected swine tissues shed sporocysts beginning 13 to 15 days postinfection and were still shedding sporocysts at the conclusion of the experiment, 30 days postinfection. Rhesus and cynomolgus monkeys were fed infected swine tissues a second time and shed sporocysts. All primates remained in good health throughout both experiments and exhibited no unusual clinical signs as a result of infection.

Animals↗
PubMed1979

The gastrointestinal absorption of PRD-92 Ea, a new anti-allergy drug.

1 The absorption of PRD-92 Ea, a new anti-allergy drug, was studied in volunteer subjects. 2 The 14C-labelled drug was administered orally and the radioactivity measured in plasma, urine and faeces. 3 Mean peak plasma concentration was 3.3 micrograms/ml, with a concentration of over 1 micrograms/ml maintained 4 h after administration. 4 The mean plasma half-life (T 1/2) was 114 min. 5 The mean percentage recovery in the urine was 9.5%. 6 Oral administration leads to significant and sustained plasma concentrations, and the oral route should be suitable for drug evaluation in clinical practice.

Adult↗
PubMed1979

Enhanced yield of antihemophilic factor and von Willebrand factor by cryoprecipitation with polyethylene glycol.

A procedure involving cryoprecipitation of human plasma in the presence of polyethylene glycol results in consistently higher yields of antihemophilic factor and von Willebrand factor than were heretofore achieved by cryoprecipitation alone. The resulting AHF and vWF are at least as pure as ordinary cryoprecipitate and can easily be further purified by additional processing. The method is expected to be especially useful in the preparation of AHF and vWF concentrates for the treatment of patients with hemophilia or von Willebrand's disease.

Blood Coagulation Factors↗
PubMed1979

Freedom from transmission of hepatitis-B of gamma-globulin and heat-inactivated plasma protein fraction prepared from contaminated human plasma by fractionation with solid-phase polyelectrolytes.

Plasma contaminated with hepatitis B surface antigen (HBsAg) and shown by others to be infectious when injected in a dilution of 1:1,000,000 in chimpanzees, was fractionated by a solid-phase polyelectrolyte (PE) procedure for its content of plasma protein fraction (PPF) and gamma-globulin (immune serum globulin; ISG). Quantitative Ausria II radioimmunoassays showed that nearly half the HBsAg was bound by the PE and could be eluted at low pH, while the rest was found in the heat-inactivated PPF. When the ISG was concentrated to 16%, the 13 mg/kg (comparable to a human dose) was injected intramuscularly in 6 chimpanzees, or when the PPF was heated at 60 degrees C for h and injected intravenously in 2 chimpanzees, there was no clinical or laboratory evidence of hepatitis B infection after 12 months, although 1 chimp of 2 who received the same material showed a borderline positive anti-HBsAg antibody result on one of 52 weekly serum samples. Since the new PE fractionation method is essentially nondenaturing, and simpler than the classical ethanol procedures, it was important to establish the noninfectivity of the final products.

Adsorption↗
PubMed1978

Purification and properties of porcine platelet aggregating factor.

Porcine platelet aggregating factor was purified from porcine plasma by a rapid batch procedure which included polyethylene glycol precipitation and adsorption on calcium citrate. The aggregating factor was separated from antihemophilic factor by gel chromatography in the presence of 1 M MgCl2. It appeared homogenous when examined by immuno- or SDS-gel electrophoresis. The molecular weight was estimated to be 10 million by exclusion chromatography. After reduction, subunit molecular weight, by sodium dodecyl sulfate (SDS)-gel electrophoresis, was 225 000. Amino acid and carbohydrate composition were similar to those reported for the bovine material. The porcine platelet aggregating factor was found to have no free sulfhydryl groups or exposed disulfide bonds. Binding of formalin-fixed washed human platelets to the aggregating factor linked to Sepharose was inhibited in 0.5 M NaCl or 2.7 M urea and reversed by the presence of free aggregating factor in a concentration-dependent manner. Ristocetin had little or no discernible effect on binding.

Amino Acids↗
PubMed1978

Comparison of the tine and Mantoux tuberculin tests. Report of the Tuberculin Subcommittee of the Researched Committee of the British Thoracic Association.

Intracutaneous (Mantoux 5 TU) and tine tuberculin tests were performed on the opposite arms of 307 people. The results of each test were read by two independent observers at either 48 or 72 hours. Positive readings were recorded in 59% of the Mantoux tests; induration was 10 mm or more in 34.7% of cases. Positive readings were recorded for 3.9% of the tine tests, and a further 15.5% were recorded in the doubtful category. The tine test is unsuitable for epidemiological use because of the high proportion of negative and doubtful results in people positive on the Mantoux test. For the same reasons its usefulness in clinical practice is very limited.

False Negative Reactions↗
PubMed1978

Intravenous infusion of salbutamol in severe acute asthma.

Out of 62 asthmatic patients admitted to hospital with an acute exacerbation of their disease, those whose symptoms had not sufficiently improved 15 minutes after an initial intensive regimen were randomly allocated to receive an intravenous infusion of either salbutamol 10 microgram/min (20 patients) or aminophylline 1 mg/min (19 patients). During the infusions, which lasted 36 hours, peak expiratory flow rates and spirometric values improved in both groups, but differences between the groups did not achieve statistical significance. Although salbutamol may be infused safely for a prolonged period to patients with acute asthma, it has no particular advantage over aminophylline. Furthermore, in patients who respond poorly to initial intensive treatment the subsequent infusion of a bronchodilator may not increase the rate of recovery from the rate that would occur naturally.

Acute Disease↗
PubMed1978

The metabolic effects of inhaled salbutamol.

1 The metabolic effects of salbutamol (5 mg) given by intermittent positive pressure breathing have been studied in eight patients with airflow obstruction. 2 No changes in plasma nonesterified fatty acids, triglyceride, glucose, insulin or cortisol were seen 1 and 4 h after administration. 3 It is concluded that inhaled salbutamol does not cause the unwanted metabolic effects reported with oral or parenteral administration, and that this is a further indication for this route of administration.

Adult↗
PubMed1978

Thecal deformity after lumbar myelography with iophendylate (Myodil) and meglumine iothalamate (Conray 280).

A study of repeat myelograms carried out in 93 patients revealed that the incidence of thecal scarring following Conray lumbar radiculography is high (61% of all cases), and only slightly lower than that found after Myodil myelography (74%). Possible factors affecting the incidence of arachnoiditis and the radiological and clinical significance of this condition are considered.

Arachnoiditis↗
PubMed1978

Preparation of the major plasma fractions by solid-phase polyelectrolytes.

The solid-phase ethylene/maleic anhydride PE's E-5 and E-100 were used to developed a flexible integrated system of batch methods for the fractionation of albumin and gamma globulin as well as the clinically important coagulation factors. Each method for the isolation and purification of the fractions or a modification of it could also be used independently or could be added onto another method or methods. Each fraction was prepared in three steps: adsorption on solid-phase PE's elution from the PE's, and concentration by ultrafiltration or by use of PEG or both. Since the methods required no organic solvent but relied primarily on electrostatic bonding, they were essentially nondenaturing. Solid-liquid phase separation was easily accomplished by centrifugation or filtration. The yield and purity of each fraction was as follows: (1) coagulation factors II, VII, IX, and X concentrates 63% and 200-fold purified; (2) AHF 43% and 52-fold; (3) vWF 43% and 71-fold; (4) PPF, as albumin, 93% yield and 92% pure; (5) albumin 92% yield and 98.5% pure; and (6) gamma globulin 92% yield and 97.5 pure. During the preparation of gamma globulin the E-100 also tended to adsorb and remove the HBSAg and infectivity, when present.

Blood Coagulation Factors↗