PubMed Health⌕ Search

Biomedical subjects

S Keating

Publications and source records attributed to S Keating.

29 records · Page 2Linked to original sources
PubMed1983

Binding of an indole derivative to micelles as quantified by phase-sensitive detection of fluorescence.

Phase-sensitive detection of fluorescence was used to measure the fractional binding of an amphipathic derivative of indole to detergent micelles. By selection of the detector phase angle, the emissions from the free and bound indole could be individually suppressed. The phase-sensitive intensity was then proportional to the concentrations of the bound and free indole, respectively. Also, the ratio of the phase-sensitive intensities, recorded at the phase angles for suppression, revealed the ratio of the fluorophore present in each environment. As the detergent concentration was increased, the measurements revealed a cooperative formation of detergent micelles and binding of the indole derivative to these micelles. The theory and procedures for this specific analysis can be applied to the analysis of any association reaction in which one of the species is fluorescent, and in which the fluorescence lifetime is altered by the binding process. An advantage of this procedure is that binding can be quantified without physical separation of the individual species.

Colloids↗
PubMed1982

Reactivity of sarcoplasmic reticulum adenosinetriphosphatase with iodoacetamide spin-label: evidence for two conformational states of the substrate binding sites.

The labeling kinetics of sarcoplasmic reticulum ATPase with the iodoacetamide spin probe N-(1-oxy-2,2,6,6-tetramethyl-4-piperidinyl)iodoacetamide were followed under conditions designed to selectively label all reactive groups. Approximately 1 mol of spin-label reacted per one 100 000-dalton ATPase chain, indicating only one residue on the enzyme had been labeled. One uniform rate of labeling was observed in the presence of Ca2+. When substrate was then added, approximately one-half of the residues showed a 10-fold increase in labeling rate while the remaining residues reacted at the initial, slower rate. Sequential labeling experiments further established that the two labeling rates correspond to the coexistence of two conformational state of the enzyme. Both Ca2+ and substrate are required to obtain an equal distribution between states, and the effect is completely reversed when substrate is removed. The iodoacetamide spin probe is known to be highly sensitive to the conformation of the ATPase binding pocket, and the residue labeled here is the one which generates broadening in the electron paramagnetic resonance spectrum on substrate binding. Due to the unique selectively of the labeling reaction, it is suggested that when both substrate and Ca2+ are bound to the enzyme, conditions which are precursory to enzyme phosphorylation, two specific conformations of the binding pocket exist in approximately at 50:50 ratio.

Adenosine Triphosphatases↗
PubMedDate not supplied

A collaborative work study program between nursing service and education.

A work study program allows students to gain academic credit while earning a salary for the nursing services they render. At the same time, they gain additional experience to increase clinical competence. The program can also serve as a recruiting device for the employing healthcare agency. The authors describe a specific work study program developed between a nursing department in a large urban medical center and a university nursing program.

Clinical Competence↗
PubMedDate not supplied

Conventional and sprinkler needle injection of magnesium insulin.

Currently available short-acting insulin preparations fail to mimic the postprandial insulin profile of non-diabetic individuals. The activity of a novel insulin designed for faster absorption has been tested after subcutaneous injection. Magnesium insulin (50 U ml-1) given by sprinkler needle was compared with unmodified human insulin (100 U ml-1) given by conventional needle and unmodified human insulin (50 U ml-1) given by sprinkler needle in normal volunteers using a euglycaemic clamp. Magnesium insulin had a significantly faster onset of action resulting in a higher exogenous insulin level by 15 min, peak level was reached after 60 min compared with 75 min for the unmodified insulins, and duration of action was significantly shorter than both unmodified insulins. No significant differences were observed between the unmodified insulins for the first 5 h after injection, indicating that the observed differences to magnesium insulin could not be attributed to the insulin concentration or the type of needle used for insulin administration. Injection of magnesium insulin prior to a test breakfast in people with Type 2 diabetes resulted in significantly lower total and 0 to 120 min areas under the glucose curve, an earlier rise in exogenous insulin levels and a higher area under the insulin curve from 0 to 120 min compared with unmodified 100 U ml-1 human insulin.

Adult↗
PubMedDate not supplied

An evaluation of percutaneous endoscopic gastrostomy feeding in AIDS.

Between October 1991 and October 1993, 17 AIDS patients (14 intravenous drug users, 3 sexually acquired) were commenced on percutaneous endoscopic gastrostomy (PEG) feeding in St James's Hospital. Indications were progressive weight loss related to severe anorexia, persistent oesophageal candidiasis (5) and absence of gag reflex (1). Two patients requested PEG tube removal after one week because of crampy abdominal pain without peritonitis. Five patients died from AIDS related infections within 6 weeks of PEG insertion. Ten patients were followed up for > 2 months (mean 5.2 months, range 2.5-15.5 months). In these 10 patients, 1 patient developed a PEG site infection which responded to topical antibiotics. There were no other complications. There was a significant (P < 0.001) increase in energy and protein intake at 2 months. Variant degrees of weight gain occurred in all patients (mean 2.6 kg) (P < 0.01). Small but significant increases in other anthropometric variables occurred. Patients who died within 6 weeks of PEG insertion were older, and had a lower serum albumin than the group who survived > 2 months (P < 0.01). A self-administered questionnaire demonstrated that the majority of patients found PEG feeding acceptable and preferable to nasogastric (NG) feeding.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Detection of benzodiazepine abuse in opiate addicts.

There is an increasing problem with benzodiazepine co-abuse in the opiate dependent population of Dublin. The importance of early detection of this co-abuse is essential as there is an increased risk of dangerous injecting practices such as sharing of needles and criminality in those who co-abuse benzodiazepines and opiates. This study was carried out in the National Drug Treatment Centre, Dublin. It aims to describe the current difficulties in identifying the co-abuse of short acting benzodiazepines including flunitrazepam in a cohort of opiate dependent patients. Using a sample of those attending the clinic it was discovered that standard methods of urinalysis failed to identify 10% of co-abuse. For those patients whose abuse of flunitrazepam is undetected on screening, clinical interventions which aim to minimise the consequence of the co-abuse and reverse the chaotic drug using patterns fail to be put in place at the earliest possible time.

Ambulatory Care Facilities↗