PubMed Health⌕ Search

Biomedical subjects

K M Barry

Publications and source records attributed to K M Barry.

6 recordsLinked to original sources
PubMed1998

Changes in regional renal blood flow after unilateral nephrectomy using the techniques of autoradiography and microautoradiography.

PURPOSE: To determine alterations in regional renal blood flow following unilateral nephrectomy using an autoradiographic technique. The role of prostaglandins and the sympathetic nervous system in the mediation of these changes was assessed. MATERIALS AND METHODS: C-14 iodoantipyrine was used as a tracer to measure intrarenal blood flow in anaesthetised rats at multiple time points following nephrectomy. Autoradiographs were produced from tissue sections. C-14 concentrations were measured from standards thus allowing blood flow values to be calculated. RESULTS: Base line values for cortical and medullary blood flow were 806 +/- 63 and 373 +/- 39 ml./100 gm./min. (mean +/- SEM) respectively. At 2 hours post nephrectomy blood flow to both the cortex and medulla increased significantly (1152 +/- 54 and 594 +/- 37; p < 0.05). Blood flow had returned to control levels by 24 hours and was maintained at 5 days post-nephrectomy. Multiple discrete regions of high blood flow within the cortex were observed. Microautoradiography defined the morphological location of these discrete regions of higher blood flow as periglomerular vasculature. Diclofenac administration did not inhibit the augmentation in cortical blood flow post-nephrectomy, while medullary blood flow fell below base line values at both 30 minutes and 2 hours following nephrectomy. Sympathetic denervation did not affect the changes in cortical blood flow seen following nephrectomy, but did ameliorate the changes in medullary blood flow. CONCLUSIONS: Significant, transient changes in regional renal blood flow occur in the residual kidney following unilateral nephrectomy. The interaction between vasoactive mediators and the autonomic nervous system which produces changes in cortical blood flow is complex. It is evident, however, that medullary blood flow is dependent on local prostaglandin production and is also influenced by sympathetic nervous supply.

Animals↗
PubMed1987

Plasma levels of amino acids correlate with motor fluctuations in parkinsonism.

Seven patients with Parkinson's disease who experienced severe motor fluctuations in response to levodopa were studied in detail with relation to the effect of dietary protein on their motor function. The levodopa dose for each patient was not changed during the period of study, and no other antiparkinsonian drugs were used. Regular and high-protein diets resulted in a marked elevation in the plasma concentrations of large neutral amino acids (LNAAs) that are known to compete with levodopa for transport across the blood-brain barrier. Despite elevated plasma levodopa levels, all patients with elevated LNAA levels experienced parkinsonian symptoms. When the amino acid level dropped while plasma levodopa levels were elevated, patients experienced relief of these symptoms. On a low-protein diet, LNAA levels remained low and all patients were consistently dyskinetic throughout the day, even though the mean plasma levodopa levels were somewhat lower than when the patients consumed a high-protein diet. A redistribution diet that is virtually protein free until supper and then unrestricted until bedtime is tolerated by patients because this simple manipulation permits near-normal daytime motor function.

Amino Acids↗
PubMed1985

Technicium as a radiolabel in the assessment of in vivo human Fc clearance.

99m-Tc was used as a radiolabel to study in vivo human clearance of IgG sensitized erythrocytes. Stannous chloride pretreatment at different doses and varying amounts of 99m-Tc were studied with respect to radiolabelling efficiency and elution. Mean in vivo clearance rates in systemic lupus erythematosus patients were significantly prolonged compared to controls. Using as little as 200 microCi of 99m-Tc per patient, in vivo human immune clearance can be determined with a minimal radiation biohazard. With this method, serial immune determinations can be performed within very short time frames, allowing for monitoring effects of immunomodulatory therapy as well as variations in disease activity.

Erythrocytes↗
PubMedDate not supplied

Identification of hydrolysable tannins in the reaction zone of Eucalyptus nitens wood by high performance liquid chromatography--electrospray ionisation mass spectrometry.

The first detailed analysis of the phenolic constituents of the reaction zones (tissue of antimicrobial defence) from the sapwood of a Eucalyptus spp. is presented. Plantation-grown Eucalyptus nitens trees with stem decay resulting from pruning wounds were sampled and extracts were prepared from healthy sapwood and from reaction zone tissue. Analysis by HPLC with ESI-MS revealed that a diverse range of hydrolysable tannins are present in both healthy sapwood and in reaction zone extracts, including over 30 gallotannins, ellagitannins and phenols. Eight tannins were unequivocally identified, including the gallotannins tri-O-galloyl-beta-D-glucose, tetra-O-galloyl-beta-D-glucose and penta-O-galloyl-beta-D-glucose, and the ellagitannins pedunculagin, tellimagrandin I, casuarinin, casuarictin and tellimagrandin II. The phenols gallic acid, ellagic acid and catechin were also identified. The ellagitannins (particularly pedunculagin) are considerably more abundant in the reaction zone than in the healthy sapwood and may contribute to the effectiveness of the reaction zone as an antimicrobial barrier.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Dietary method for reducing fluctuations in Parkinson's disease.

Motor fluctuations and non-response to carbidopa-levodopa (Sinemet) therapy are major problems in the long-term management of Parkinson's disease. Levodopa manipulation, addition of adjuvants, and drug holidays are often unsuccessful. Others have shown that the clinical state of stabilized Parkinsonians can be reversed with intravenous administration of large neutral amino acids. Reasoning that dietary protein might precipitate motor oscillations and non-response, a low-protein daytime diet (7 g) was offered to fifteen patients. Eighty-six percent of this sample demonstrated immediate sensitivity to Sinemet. While on a low-protein diet, patients' clinical function was predominantly choreatic. Eight patients required a 10-60 percent reduction in their daily levodopa dose in order to minimize this choreatic tendency. Discontinuation of adjuvants did not compromise motor independence. Conversely, while on a high-protein diet (160 g), patients were predominantly immobile with markedly elevated plasma amino acid and levodopa levels. Consequently, elimination of dietary protein from breakfast and lunch can offer an effective and easily modified method for the amelioration of motor fluctuations and non-response to Sinemet in Parkinson's disease during working hours.

Adult↗