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Biomedical subjects

R Major

Publications and source records attributed to R Major.

16 recordsLinked to original sources
PubMed2001

Reduction of indicator organisms during biological solubilization of metals: a pilot study.

Laboratory and pilot scale studies on the biological solubilization of metals from undigested raw sludge were carried out using elemental sulphur as the energy source. Metals (Cu, Zn, Ni and Cd), pH, sulfate and indicator bacteria [total coliforms (TC) faecal coliforms (FC) and faecal streptococci (FS)] were used to evaluate the system effectiveness. This paper does not report the detailed design and operational data of the pilot plant (available elsewhere [1]) but focuses on the biological tests carried out at the Main Wastewater Treatment Plant in Toronto from July to December, 1997. Since the indicator bacteria are injured from exposure to low pH and potentially toxic metal concentrations, improved alternative methods for their enumeration and their ability to repair acid-metal induced injury in a resuscitation medium (CASO tryptone soya broth) were also investigated. Resuscitation was not effective in repairing cells injured during bacterial leaching. The MPN technique (using lauryl tryptose broth) for enumerating indicator bacteria (total coliforms) gave higher counts and was therefore superior to the spread plate technique (using m-Endo agar) in recovering bacteria from acidic leached sludge (biosolids). However, the coliform bacterial counts from raw sludge were similar by the two methods. This study indicated that the biological solubilization process could significantly reduce the pathogenic indicators. Concentrations of TC, FC and FS in the leached biosolids from the solubilization tank were lower than concentrations in the raw sludge by 4 to 6 orders of magnitude and the finished product (biosolids) met US. EPA requirements for pathogen and metal concentrations for Class A biosolids to be used on agricultural land.

Agriculture↗
PubMed1981

A common-source outbreaks of ornithosis in veterinary surgeons.

Presumed or confirmed ornithosis developed in 15 of 46 veterinary surgeons within 3 weeks of their attending a training course on the supervision of poultry processing plants. A duck processing plant was the probable source of infection. The attack rate in those visiting this plant was 44% (15/34) and the rate in those who had close contact with duck feathers was 1.7 times the rate in the remainder of the group who visited the plant. The incubation period ranged from 6 to 20 days. This is the second outbreak of the duck-associated ornithosis to be recognised in the U.K.

Animals↗
PubMed1981

Ornithosis in poultry workers.

An outbreak of ornithosis in duck workers in the winter of 1979 and spring of 1980 was discovered by the investigation of a cluster of cases in Norfolk. A serological survey showed that 61% of duck workers but only 23% of control poultry workers had chlamydia group antibody titres of greater than or equal to 1:8. Altogether 9% of duck workers in the survey had antibody titres greater than or equal to 1:32 and a clinical illness suggestive of ornithosis. The proportions of seropositive tests and clinical attack rates were highest in workers eviscerating ducks and lowest in farm workers. It is suggested that a clinical history of contact with poultry should be considered relevant in the diagnosis of ornithosis and that clinicians caring for poultry workers should consider the possibility of ornithosis as an occupational disease.

Adult↗
PubMed1978

Effect of pimozide on the improvement in learning produced by self-stimulation and by water reinforcement.

When rats self-stimulate immediately after the training trial of an appetitive task their performance on a retention test is improved the next day. In the present study, this improvement was blocked by pretraining injections of pimozide, a dopaminergic blocker. In a second experiment, injections of pimozide retarded learning on the same task when the learning was reinforced by drinking water, but had no effect on learning which occurred in the absence of a reinforcer. The data made the hypotheses that the animal's behavior was a result of an action of primozide on sensory or motor mechanisms, or that the drug produced state-dependent effects, highly unlikely. We concluded that neural systems involving dopamine mediate an effect of reinforcing events on behavior.

Animals↗
PubMedDate not supplied

Isosorbide 5-mononitrate pharmacokinetics in humans.

When isosorbide 5-mononitrate was intravenously infused at a rate of 4 mg h-1 for 2.5 h to five human subjects, its concentrations in plasma increased slowly to 185 ng ml-1 +/- 5 per cent C.V. at 2.5 h and a steady-state plasma level was not reached during the infusion. When the infusion was discontinued, plasma drug concentrations declined with an elimination half-life of 4.2 h +/- 6 per cent C.V. The systemic clearance after the infusion doses was 132 ml min-1 +/- 18 per cent C.V. and the volume of distribution was 48.4 +/- 16 per cent C.V. After equal oral doses of 10 mg, the peak plasma isosorbide 5-mononitrate concentration of 191 ng ml-1 +/- 16 per cent C.V. was reached at 1.1 h +/- 30 per cent C.V., and plasma levels declined with a terminal half-life of 4.9 h. The complete systemic availability of isosorbide 5-mononitrate indicated that pre-systemic elimination after the oral doses was negligible. A one-compartment open model appeared adequate to describe the plasma level data after intravenous infusion and oral dose. After single oral doses of 10 mg isosorbide dinitrate, the peak plasma concentration of the 5-mononitrate metabolite of 72 ng ml-1 +/- 27 per cent C. V. occurred at 1.7 h +/- 41 per cent C.V. Approximately 50 per cent (range 22--68 per cent) of the oral dose of isosorbide dinitrate circulated in plasma as the 5-mononitrate metabolite. The pharmacokinetics of isosorbide mononitrates are markedly different to those of the parent dinitrate and these differences follow from the greater systemic availability and volume of distribution of the mononitrates.

Adult↗