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Biomedical subjects

G Fitzgerald

Publications and source records attributed to G Fitzgerald.

At least 19 recordsLinked to original sources
PubMed1992

Cloning and partial sequencing of the proteinase gene complex from Lactococcus lactis subsp. lactis UC317.

The proteinase genes from Lactococcus lactis subsp. lactis UC317 were identified on a plasmid, pCI310, which is a deletion derivative of a cointegrate between pCI301, the 75 kb Lac Prt plasmid from UC317 and the 38.5 kb cryptic plasmid from that strain. The prt genes were cloned using a replacement cloning strategy whereby fragments from pCI310 were exchanged with the equivalent fragments in pNZ521, which contains the cloned proteinase genes from L. lactis subsp. lactis SK112. This generated two plasmids which encoded a cell-envelope-associated and a secreted proteinase, respectively. Specific regions of the UC317 structural prtP gene known to encode seven of the amino acids essential for substrate cleavage specificity were sequenced and compared with the known sequences of prt genes from L. lactis strains SK112, Wg2 and NCDO763. In spite of various differences that were detected in the nucleotide sequence of this region, it appears that these seven amino acids in strains UC317 and NCDO763 are identical, and represent a combination of three of the amino acids from SK112 and four from Wg2. These results indicate that the UC317 proteinase is a natural hybrid of the SK112 and Wg2 proteinases.

Amino Acid Sequence↗
PubMed1992

Gilles de la Tourette's syndrome: a case study.

Tourette's Syndrome was first described by Gilles de la Tourette in 1885. Previously thought to be a rare neuropsychiatric disorder, its prevalence is now estimated at 0.05%. In Canada, this would mean approximately 12,000 people are affected. The rapid growth of knowledge in the neurosciences has led to better understanding and treatment of this disorder. Tourette's Syndrome is characterized by motor tics, usually beginning in the face and progressing to other areas, and by vocal tics, such as hissing, snorting, and barking. Fifty percent also develop copralalia. The age of onset is between 2 and 15 years of age but its complex symptomatology and its waxing and waning course delays diagnosis. This paper will describe the disease process including etiology, signs and symptoms, and treatment. The main focus will be on a case study which will depict how this syndrome affected the life of one woman. The multidisciplinary approach required to assist the severely affected individual to return to her family following successful treatment will be described.

Adult↗
PubMed1991

Electron redistribution on binding of a substrate to an enzyme: folate and dihydrofolate reductase.

The migration of electron density of a substrate (folate) on binding to an enzyme (dihydrofolate reductase) is studied by a quantum-mechanical method originally developed in solid state physics. A significant polarization of the substrate is induced by the enzyme, toward the transition state of the enzymatic reaction, at the same time giving rise to "electronic strain energy" in the substrate and enhanced protein-ligand interactions. The spatial arrangement of protein charges that induces the polarization is identified and found to be structurally conserved for bacterial and vertebrate dihydrofolate reductases.

Binding Sites↗
PubMed1991

Changes in the electron density of the cofactor NADPH on binding to E. coli dihydrofolate reductase.

Quantum-mechanical electron density calculations reveal that a significant polarization is induced in the cofactor NADPH (reduced nicotinamide adenine dinucleotide phosphate) on binding to the enzyme dihydrofolate reductase. The calculations indicate that electron density corresponding to approximately 0.7 electron charges is shifted within the molecule, extending over more than 20 A. Further calculations on proposed enzyme mutants show that the polarization of NADPH on binding to DHFR is, in large part, induced by a motif of three positively charged residues. This motif was also identified to be directly responsible for the positive electrostatic potential surrounding the cofactor binding site in the enzyme. The possibility of this long-range polarization of NADPH was originally proposed based on a previous study of ligand binding to DHFR where a conserved structural motif of three positively charged residues was found to play a major role in polarizing the substrate folate over its entire length of 18 A.

Arginine↗
PubMed1991

Granulomatous prostatitis: a clinicopathological study.

In a clinicopathological study of granulomatous prostatitis, we have found two distinct histological patterns. Approximately one third of cases consisted of localized, often elongated or stellate lesions, resembling rheumatoid nodules. Where clinical details were available, most of these cases had a history of previous transurethral resection. The remaining cases showed more diffuse involvement of the prostate, with lesions centred on ducts and glands, and were not associated with previous prostatic surgery or systemic illness. Immunohistochemical studies of the associated inflammatory infiltrate showed an apparently random distribution of T- and B-lymphocytes in the former group, while in the latter group there was a concentration of T-cells in and around damaged ducts and glands, suggesting a possible immune-mediated destruction of these structures.

Adult↗
PubMed1990

Enzyme immunoassay measurement of the urinary metabolites of thromboxane A2 and prostacyclin.

We have used a recently developed enzyme immunoassay (EIA) method for measuring urinary concentrations of TXB2, 6-keto PGF1 alpha, 2,3-dinor-TXB2, 2,3-dinor-6-keto PGF1 alpha and 11-dehydro-TXB2 using acetylcholinesterase from Electrophorus Electricus coupled to TXB2, 6-keto PGF1 alpha and 11-dehydro-TXB2. Urinary PGI2 and TXA2 breakdown products and their metabolites were extracted from 3-40 ml of urine corresponding to 100 mumoles creatinine. Measurements were performed after Sep-Pak extraction and thin layer chromatography separation in a system that allows separation between dinor- and parent derivatives. Because of the relatively high cross reactivity (10-15%) of the anti-TXB2 serum with 2,3-dinor TXB2 and the anti-6-keto PGF1 alpha serum with 2,3-dinor-6-keto PGF1 alpha, measurements were done using 3 antisera (anti-TXB2 and anti-6-keto PGF1 alpha diluted 1/50,000, anti 11-dehydro-TXB2 diluted 1/200,000). The reproducibility of the technique was assessed by measuring the same urine stored frozen in aliquots together with each series of samples (Coefficient of variation 6-12% (n = 20), depending on the compound). In addition, the use of a different solvent system for the thin layer chromatography did not affect the results although the migration of the compounds was modified significantly. Determination of the urinary excretion of TXB2 and prostacyclin metabolites in 17 healthy individuals by this method provided results in agreement with those obtained by other methodologies. In addition, comparisons made between EIA and gas chromatography/mass spectrometry analysis showed good correlation between the urinary metabolites as determined by each technique (r = 0.98).

Adult↗
PubMed1990

Preliminary studies on the use of propofol in the domestic pigeon (Columba livia).

The anaesthetic propofol was investigated in domestic pigeons (Columba livia). The agent was administrated intravenously, in one group of birds as an adjunct to ketamine hydrochloride, and careful monitoring was performed. The dose of 14 mg kg-1 of propofol was based on allometric scaling for its use as a sole agent. Propofol anaesthesia was characterised by smooth rapid induction and good muscle relaxation but was only of short duration, ranging from two to seven minutes, and seemed to cause a marked respiratory depression. Indeed, a very narrow safety margin for propofol was observed in pigeons when ventilation was not assisted. The agent may have applications in avian anaesthesia but these are likely to be limited.

Anesthesia↗
PubMed1989

Effects of caregiving on caregiver spouses of stroke victims.

The purpose of this study was to determine the effects of caregiving on caregiver spouses of stroke victims and the change in these effects over time. Twenty-nine effects of caregiving were identified. These effects were grouped into four major categories. The number of effects in the categories of loss of freedom and social activities and change in role, decreased over time. The effects in decrease in physical and emotional health and marital discord increased over time. The presence of a chronic illness in the caregiver and/or a second chronic illness in the stroke victim appeared to influence the escalation of effects of caregiving. An additional factor may be the length of time in the caregiving role. Nursing implications suggested by this study relate to helping the caregivers in the early mobilization of their own informal resources for respite care and to assisting caregivers to deal with the emotional aspects of caregiving.

Adaptation, Psychological↗
PubMed1987

Energy requirements of pregnancy in Scotland.

Measurements of energy intake, basal metabolic rate, body weight and composition, and physical activity were made on 88 women throughout pregnancy. Mean weight gain (from 10 wk to 40 wk gestation) was 11.7 kg, birthweight 3370 g, and placental weight 641 g. Maternal fat gain (from 10 wk) calculated by three methods was 2.1 kg. The total rise in basal metabolism for the whole of pregnancy was calculated to be 126 MJ (1 MJ = 239 kcal). The total increase in energy intake was estimated as 88 MJ. There was little evidence of any changes in either the energy cost of physical activity or the time spent in these activities. The total energy cost of laying down fetal and maternal tissues and the increased metabolism was 281 MJ, which was offset by a possible increase in energy intake of only 88 MJ. The most likely explanation for the deficit of 193 MJ is that many small reductions in energy expenditure occurred which were not detectable by the methods used.

Adipose Tissue↗
PubMed1987

The effect of nutritional counselling on diet and plasma EFA status in multiple sclerosis patients over 3 years.

The dietary intake of 83 people with multiple sclerosis (MS) was assessed by the 7-day weighed intake method prior to dietary advice and at 6-monthly intervals thereafter up to 36 months. The P:S ratio of the diet increased from an initial value of 0.8 to 1.5 after 6 months and 1.34 at 36 months. Biochemical investigation of plasma essential fatty acid (EFA) status specifically linoleic, eicosapentanoic and docosahexanoic acids showed significant correlations with diet. Concurrent 6-monthly neurological and physiotherapy assessments were also carried out, the neurological results are discussed in relation to a nutrient scoring system.

Activities of Daily Living↗
PubMed1985

Is nutritional status endangered by virtually no extra intake during pregnancy?

In the course of a multinational study on energy requirements in pregnancy and lactation, the food intake of 67 pregnant women in Glasgow was measured by the use of the individual weighed inventory technique, for 3 or 5 consecutive days every 6 weeks (in 21 women), every 4 weeks (in 23 women), or every 2 weeks (in 23 women). Data were obtained in the pre-pregnant state in 12 women. Rises in energy intakes were small and gradual in the first 34 weeks of pregnancy, the mean being about 50 kcal (210 kJ)/day, but in the remaining weeks of pregnancy, intakes rose by about 150 kcal (630 kJ)/day. The total extra energy intake therefore represented less than 20 000 kcal (84 MJ), as opposed to theoretical estimates of requirements of 80 000 kcal (335 MJ). Energy-saving mechanisms may have resulted in reductions in physical activity, but this was not obvious in the study population. However, there was depression of basal metabolic rates in the first half of pregnancy, which could produce considerable energy savings.

Adult↗
PubMed1981

Inhibition of reverse transcriptase by tyrosinase generated quinones related to levodopa and dopamine.

Several derivatives of levodopa have been shown to be potent inhibitors of the sulfhydryl enzyme, RNA dependent DNA polymerase, reverse transcriptase (RT). In the presence of the polyphenol oxidase, tyrosinase, the inhibitory values were between 10(-6) M and 10(-5) M. Structure-activity studies revealed that active oxidation or reduction was necessary for this potent inhibitory response. Spectrophotometric analysis showed that the presence of both the quinone and quinol was required for maximum inhibitory activity. These data suggest that the common intermediate of oxidation of quinols or reduction of quinones (i.e., semiquinone) is the active species. The use of tyrosinase provides a convenient model for the detection of the actual inhibitory interaction of a free-radical (semiquinone) with a biologically important macromolecule, reverse transcriptase.

Avian Myeloblastosis Virus↗
PubMed1978

Effect of peroral administration of xylitol on exocrine secretions of monkeys.

The effects of the administration of xylitol on the biochemical properties of monkey parotid and submandibular saliva and lacrimal fluid were investigated. Monkeys (Macaca mulatta) were fed either a sucrose or xylitol diet for 3 days. Ingestion of xylitol was associated with a significant increase of the activity of the salivary lactoperoxidase. The concentration of protein was also increased. Higher lactoperoxidase activity was found in parotid than in submandibular saliva. The concentrations of inorganic phosphate, calcium and SCN ions were practically unaffected. The concentration of SCN ions in pilocarpine stimulated monkey saliva was low (less than 5.5 mg/liter). Peroral administration of 2.5 g of xylitol or sorbitol per day to M. fascicularis resulted in almost similar levels of salivary lactoperoxidase activity. The administration of xylitol orally or by gastric intubation was not found to affect the concentration of lactoperoxidase, protein, phosphate, and SCN and iodine ions in lacrimal fluid. The results suggest that specific dietary sugars have a selective effect on the biochemical properties of saliva.

Animals↗