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Biomedical subjects

J MacLeod

Publications and source records attributed to J MacLeod.

At least 37 records · Page 2Linked to original sources
PubMed1983

Differences in reaction characteristics between human and bovine-based control materials for iron determination.

Reaction rate studies were carried out on various quality control specimens using a ferrozine iron determination kit. The time required for complete color formation differed among the various materials tested. Quality control materials of bovine origin required a much longer incubation time for full color formation. Using a fixed incubation procedure, the bovine controls would give a falsely low result. The present study suggests that caution is indicated when quality control data using bovine materials are interpreted.

Animals↗
PubMed1982

Enhancement of human rotavirus infectivity in a monkey kidney cell line by human expressed breast milk.

Eight of forty (20%) human expressed breast milks enhanced the infectivity of human rotavirus (HRV) when assayed by immunofluorescence in a monkey kidney cell line (LLC-MK2). This enhancement was demonstrated with two HRV strains, one derived from a fecal specimen of a child with acute gastroenteritis, the other a tissue culture adapted strain. The phenomenon could have important implications in the pathogenesis of HRV infections and in future vaccine programs.

Animals↗
PubMed1982

Neonatal rotavirus infection: role of lacteal neutralising alpha1-anti-trypsin and nonimmunoglobulin antiviral activity in protection.

Expressed breast milks (EBMs) were collected from mothers of rotavirus (RV)-excreting babies and from mothers whose babies were RV free during an outbreak of asymptomatic RV infection in a newborn nursery to determine the role of lacteal anti-RV neutralising activity, alpha1-anti-trypsin activity, and nonimmunoglobulin antiviral factor in protection of neonates from RV infection, and although all of the above factors were present in the majority of the EBMs, no correlation could be found between their presence in EBM and protection from RV infection. A significant rise in both neutralising activity and subgroup 2 antibodies, was demonstrated in the EBM of one mother who experienced a subgroup 2 RV-associated diarrhoea during lactation. However, the alpha1-anti-trypsin activity and the nonimmunoglobulin antiviral levels remained the same. The importance of these factors in passive immunity with reference to virus dose is discussed.

Antibodies, Viral↗
PubMed1976

Coping with the aggressive patient: an alternative to punishment.

Extremely aggressive patients in mental institutions constitute a threat to staff and other patients that usually necessitates the use of physical restraints. With chronically aggressive patients this cycle of behaviors is defeating for both the staff and the patient. In this case history the authors describe how positive and negative reinforcement and shaping were used to alter the previously unmanageable aggression of a 36-year-old male psychiatric patient.

Adult↗
PubMed1975

T-mycoplasmas and human infertility: correlation of infection with alterations in seminal parameters.

The presence of T-mycoplasmas in semen specimens from 625 men with infertility of unknown etiology was correlated with seminal cytologic findings. A change in the distribution toward higher ejaculate volumes and lower counts was demonstrated in the 246 patients with positive T-mycoplasma cultures, compared with the 379 patients with negative cultures. There was a significant increase in the number of tapering forms and spermatids in the T-mycoplasma-positive group. The increases in aberrant forms occurred at the expense of the oval and microcephalic forms. This change in the cytologic picture is consistent with the "stress" pattern seen in viral infections and allergic reactions, with the exception of the specific decrease in microcephalic forms. Relatively fewer patients with T-mycoplasmas in their semen had a high-level spermatozoal motility, compared with those lacking T-mycoplasmas. More than half again as many patients with T-mycoplasma infections had the poorest levels of spermatozoal motility. Infertile patients with T-mycoplasma infections had an over-all decrease in semen quality compared with those lacking demonstrable T-mycoplasmas.

Humans↗
PubMed1975

Effect of growth temperature on the accumulation of glucose-oxidation products in Pseudomonas fluorescens.

The effect of the growth temperature, on the accumulation of glucose-oxidation products, was examined in aerated cultures with carbon excess in two strains of Pseudomonas fluorescens. At low growth temperatures (0 and 5 degrees C), 2-ketogluconate (KG) a-cumulated in the medium as the major oxidation product of glucose (up to 70%) before further metabolism. As the growth temperature was increased, the amount of 2-KG found to accumulate in the medium from glucose oxidation decreased. At a growth temperature of 20 degrees C, up to 25% of the glucose originally added accumulated in the medium as 2-KG. At the optimum growth temperature of 30 degrees C or above, no 2-KG was detected at any time during growth with glucose. Similar results were obtained when gluconate was used as the sole carbon and energy source. The results demonstrated a differential effect of growth temperature on the accumulation of oxidation products from glucose and gluconate. At low growth temperatures the major route for the catabolism of glucose and gluconate was the direct oxidative non-phosphorylated pathway.

Gluconates↗
PubMed1975

Effect of temperature on the activity and synthesis of glucose-catabolizing enzymes in Pseudomonas fluorescens.

The activity of the enzymes of the oxidative non-phosphorylated pathway, glucose and gluconate dehydrogenases, were not significantly affected by changes in the assay temperature. Both enzymes demonstrated only a threefold difference in activity when compared at assay temperatures of 30 degrees C and 5 degrees C. In contrast, the enzymes involved in the direct phosphorylation and catabolism of glucose or its oxidation products, gluconate and 2-ketogluconate, exhibited a more pronounced response to decreasing assay temperatures. At least one enzyme in each pathway, involved in the direct phosphorylation and catabolism of glucose or 2-ketogluconate (2KG), demonstrated an eightfold decrease in activity with a decrease in assay temperature from 30 degrees C to 5 degrees C. A similar decrease in assay temperature resulted in a fivefold decrease in activity of the enzymes involved in the direct phosphorylation and catabolism of gluconate. The observed differential effect of temperature on the activity of the enzymes of glucose catabolism and on the accumulation of direct oxidation products during growth with glucose in P. fluorescens E-20 is discussed. Growth with glucose at 5 or 20 degrees C resulted in high induced levels of all glucose-catabolizing enzymes examined when compared with the levels of these same enzymes in pyruvate-grown cells. However, only low levels of glucose dehydrogenase were detected during growth at 30 degrees C with glucose, gluconate, or 2-KG. Similarly, only low levels of gluconate dehydrogenase were detected during growth with glucose at 30 degrees C, although a weak induction was observed during growth with gluconate or 2-KG at 30 degrees C. The levels of 2-KG kinase plus KPG reductase during growth at 30 degrees C were undetectable with glucose, weakly induced with gluconate, and fully induced with 2-KG. High induced levels of glucose dehydrogenase, gluconate dehydrogenase, and 2-KG kinase plus KPG reductase were present during growth at 20 degrees C with glucose or 2-KG. The low levels of glucose and gluconate dehydrogenases present at a growth temperature of 30 degrees C was not due to heat lability of the enzymes at this temperature. The low amounts of these two enzymes during growth with glucose at 30 degrees C probably prevented sufficient inducer(s) formation from glucose to allow induction of enzymes of 2-KG catabolism. The results demonstrated that temperature may regulate the pathways of glucose dissimilation by regulating, either directly or indirectly, the activity and synthesis of the enzymes involved in these pathways.

Alcohol Oxidoreductases↗