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Biomedical subjects

I McDonald

Publications and source records attributed to I McDonald.

At least 37 records · Page 2Linked to original sources
PubMed1992

A protective role for nitric oxide in the oxidative modification of low density lipoproteins by mouse macrophages.

Low density lipoproteins (LDL) oxidatively modified by macrophages have been shown to be atherogenic in ex vivo studies. We studied the potential role of nitric oxide (NO), a free radical produced by macrophages, in LDL modification. Human LDL (1 mg/ml) were incubated with mouse peritoneal macrophages in Ham's F-10 medium. The cells were then stimulated by interferon-gamma and tumor necrosis factor-alpha to increase their production of NO from 1.3 to 12.2 microM in 24 h, as measured by nitrite. Lipid peroxidation of LDL, as measured by thiobarbituric acid-reactive materials (TBARS), was reduced in stimulated cells in a time-dependent manner. At 24 h, the decrease was about 27%. In the presence of an NO synthase inhibitor (NG-aminophomoarginine), the generation of NO was diminished and the protection against LDL lipid peroxidation was reversed. The extent of LDL protein modification was also assessed by examining its electrophoretic mobility. It was found that macrophage NO reduced the change in LDL electromobility. These data indicate that the production of NO may inhibit the oxidative modification of LDL with cytokine-stimulated macrophages. We suggest that NO plays a protective role in limiting macrophage-induced LDL modification.

Animals↗
PubMed1992

Randomized controlled trial of cyclophosphamide, warfarin and dipyridamole in idiopathic membranous glomerulonephritis.

40 patients with idiopathic membranous glomerulonephritis were randomized to receive either no treatment or a regime of cyclophosphamide for 6 months, and warfarin and dipyridamole for two years. During the two years of the trial there was no significant deterioration in renal function in either group. A significantly greater improvement in urinary protein excretion was, however, observed at all time points in the treatment group. Plasma albumin was also significantly higher in the treatment group at 18 and 24 months. As progressive deterioration in renal function in membranous glomerulonephritis is associated with persistent heavy proteinuria these results suggest a beneficial effect of treatment.

Cyclophosphamide↗
PubMed1983

The effect of changes in the amount of energy infused as volatile fatty acids on the nitrogen retention and creatinine excretion of lambs wholly nourished by intragastric infusion.

The nitrogen balance and creatinine excretion of wether lambs of 30-48 kg, wholly nourished by the intragastric infusion of nutrients, were measured in two experiments. Four lambs were used in each experiment. In Expt 1 a constant amount of casein was infused into the abomasum (640 mg N/kg body-weight (W)0.75 per d) and the amount of volatile fatty acids (VFA) infused into the rumen ranged from 0 to 670 kJ/kg W0.75 per d as six increments. Expt 2 was of similar design but two levels of casein were infused (530 and 1060 mg N/kg W0.75 per d) and, with each level of casein, VFA infused ranged from 0 to 700 kJ/kg W0.75 per d as seven increments. Daily creatinine excretion was not constant, but varied between 2-d means with standard deviations of between 7.1 and 16.5% (average 13.1%) of the over-all means. There was an apparent correlation between creatinine excretion and the amount of energy infused in six out of eight lambs. There was no effect of the amount of casein infused. In both experiments N balance was negative only when the amount of energy infused was substantially below published values for energy maintenance. In Expt 1, N equilibrium was calculated to be achieved at a gross (VFA plus protein) energy infusion level of 162 (SE 29) kJ/kg W0.75 per d. In Expt 2 it was observed that, at a given level of energy infusion, N retention was greater when the amount of energy had been increased from the previous level, than when it had been decreased. It is concluded that the animal appears to allocate available amino acids to protein synthesis, rather than to oxidation, even when in negative energy balance. It is also concluded that enhanced N retention observed when the amount of energy infused had been increased represented compensation after a period of energy restriction.

Animals↗
PubMed1982

Bilateral replacement of the hip and knee in rheumatoid arthritis.

Twenty-six patients with rheumatoid arthritis who had undergone bilateral replacement of the hip and knee were reviewed at a mean follow-up time of 51.6 months. A further operation was necessary in five patients due to complications of replacement of the knee, and seven patients still had significant pain in at least one replaced joint. There were no cases of infection due to operation. Seventeen of the patients still used walking aids, but one-third of these did so because of pain in joints that had not been replaced. Patients preferred painless total replacement of the hip to that of the knee.

Adult↗
PubMed1981

The effects of protein degradability and food intake on milk yield and composition in cows in early lactation.

1. In two experiments measurements were made of food intake, live-weight change, milk yield and milk composition in early lactation when dairy cows were given diets containing varying proportions of protein as fish meal (low rumen degradability) or as groundnut meal (high rumen degradability). In a preliminary trial measurements were also made with cows given supplements of either fish meal or barley and fed at a restricted level of feeding. 2. When metabolizable energy (ME) intake exceeded 160 MJ/d there was no evidence of responses to changes in protein degradability, ut at ME intakes below 135 MJ/d increases in the supply of undegradable protein led to increases in fat-corrected milk yield, protein content and live-weight loss. 3. The interaction between energy intake and protein degradability is unexpected because net protein:net energy requirement increases as milk yield increases, but may be explained in terms of differential effects of changing rumen outflow rates on degradabilities.

Animals↗
PubMed1980

Measurement of the rates of protein synthesis in rabbits. A method for the estimation of rates of change in the specific radioactivities of free amino acids during continuous infusions.

1. A method is described by which, from analysis of terminal samples, the rate constants that define the changes in specific radioactivity of free amino acids during continuous infusions can be estimated. The method involves the infusion of 3H-labelled and 14C-labelled forms of an amino acid for different, but overlapping, periods. 2. The procedure was developed for infusions of proline and tyrosine into New Zealand White rabbits and the rate constants were determined for blood and muscle. 3. The rate constant for equilibrium of radioactive free proline was much lower in muscle than in blood, and indicated that a plateau condition may not be attained in muscle by the end of a 6 h infusion. 4. Comparison of the ratio of areas under the curves of estimated specific radioactivity plotted versus time with the 3H/14C ratio of bound amino acid in muscle protein suggested that radioactive proline and tyrosine may be incorporated preferentially from an extracellular rather than an intracellular source.

Animals↗
PubMed1979

Eikenella corrodents infection of the hand.

The clinical presentation and course of two patients with Eikenella corrodens infection of the hand is recorded. This recently recognised organism must not be regarded as a harmless commensal and should be differentiated from the Bacteroides group because of its resistance to clindamycin. Radical surgical debridement is the most important aspect of therapy.

Adult↗
PubMed1978

A comparative assessment of carbuterol, fenoterol and hexoprenaline in allergic asthma.

Carbuterol tablets (2,0 mg) were compared with the tablets of fenoterol (2,5 mg) and hexoprenaline (1 mg). The three drugs were shown to be equally effective for a period of 4 hours, but carbuterol and fenoterol exerted a statistically significant bronchodilating action for 7 and 8 hours respectively, while the action of hexoprenaline lasted for 4 hours in the majority of patients. The aerosols of carbuterol (200 mg) and fenoterol (400 mg) appeared to be similar in inhibiting exercise-induced asthma, whereas hexoprenaline (200 mg) did not appear to be as effective.

Adolescent↗
PubMed1978

Purification and characterization of human prostatic acid phosphatase.

Human prostatic acid phosphatase (orthophosphoric monoester phosphohydrase, EC 3.1.3.2) is purified to homogeneity by standard procedures which include CM-Sephadex, Con A affinity chromatography and gel filtration. The purified enzyme is antigenically specific and has a M.W. of 100,000 with subunit M.W. of 48,000. However, the enzyme exhibited charge heterogeneity. Two major electrophoretic or chromatographic isozymic forms of PAP were separated by DEAE-Sephadex chromatography and their immunochemical identity was studied by immunodiffusion before and after the neuraminidase digestion. Quantitative precipitin and inhibition experiments showed immunological identity of the two chromatographic isozymes. Immunologic specificity of this enzyme resides on the protein moiety rather than the carbohydrate residue, although the latter group is mostly responsible for the charge group heterogeneity of the enzyme.

Acid Phosphatase↗
PubMed1978

Human prostatic acid phosphatases: III. Counterimmunoelectrophoresis for rapid identification.

When serial dilution of standard prostatic acid phosphatases (PAP) was reacted with constant amounts of anti-PAP serum by counterimmunoelectrophoresis (CIEP), the detection end point of enzyme concentration was 0.25 ng in a 10 microliter sample volume. The PAP concentrations in unknowns can be quantitated by comparing the dilution end points of reference PAP with the testing samples. Serum PAP levels were determined by a radioimmunoassay (RIA) and CIEP using normal male and female sera and serum samples from patients with prostatic cancer and nonprostatic tumors. An excellent correlation was observed between the two assay results. According to RIA data, the concentration of PAP higher than 0.4 ng per 10 microliter (or 4.0 ng per 100 microliter) signify the elevation of serum or bone marrow PAP level beyond normal range (normal value 1.6 +/- 0.8 ng/100 microliter). Thus, the CIEP assay will be a simple and reliable screening method for the serum PAP levels in the clinical diagnosis of prostatic cancer.

Acid Phosphatase↗
PubMed1977

The effects of pregnancy and lactation on copper and zinc retention in the rat.

1. The accretion of copper and zinc in maternal tissues, conception products and postnatal offspring of the rat was determined at different stages of pregnancy and lactation. 2. Equations relating the weight of the bodies of the developing young and of the amounts of Cu and Zn in them to the time that has elapsed since conception showed that, early in pregnancy, the specific rates of accretion of Cu or Zn were greater than that of weight, but declined more rapidly as development continued. The instantaneous rates of accretion of both metals rose throughout pregnancy but only that of Cu continued to increase during lactation. 3. The amount of Cu in the maternal body rose significantly during pregnancy and declined thereafter, but relatively small changes in its Zn content occurred. 4. The results are discussed in relation to the relative demands for these metals during pregnancy and lactation.

Animals↗
PubMed1977

Rates of rumen fermentation in relation to ammonia concentration.

1. Four sheep were fed from automatic continuous feeders on whole barley fortified with graded levels of a urea solution. This approach was to a large extent successful in maintaining relatively steady states of rumen ammonia concentration. 2. Rates of barley fermentation in the rumen at various rumen NH3 concentrations were assessed by measuring the disappearance of barley dry matter from polyester bags suspended in the rumen of these sheep. 3. The minimal NH3 concentration for maximal rate of fermentation was estimated as 235 mg/l rumen fluid.

Ammonia↗