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Biomedical subjects

S Keating

Publications and source records attributed to S Keating.

At least 37 records · Page 2Linked to original sources
PubMed1990

The viability of articular cartilage in fresh osteochondral allografts after clinical transplantation.

The articular cartilage of four fresh osteochondral allografts was biopsied after transplantation, and its viability was studied by autoradiography. The biopsy specimens were labeled with both 3H-cytidine, for newly synthesized ribonucleic acid, and 35S-sulphate, for newly synthesized proteoglycans. The cartilage of a lateral humeral condylar graft at twelve months had 96 to 99 per cent labeled chondrocytes, the articular cartilage of a medial femoral condylar graft at twenty-four months showed 69 to 78 per cent labeled chondrocytes, and the cartilage of a medial tibial-plateau graft at forty-one months had 90 per cent labeled cells. At six years, a lateral tibial-plateau graft had 37 per cent labeled chondrocytes.

Adult↗
PubMed1988

Methylation deficiency causes vitamin B12-associated neuropathy in the pig.

Pigs were treated with N2O which is known to impair vitamin B12 function in vivo. Such pigs demonstrated an inability to gain weight, progressive ataxia, and spinal neuropathy. The ataxia was totally and the neuropathy partially preventable by dietary methionine supplementation. Methionine synthase activity was inhibited in both the liver and brain. There was a marked elevation of S-adenosylhomocysteine in the neural tissues and a concomitant failure of S-adenosylmethionine to rise and thus maintain the methylation ratio, except when supplementary dietary methionine was added. In contrast, the methylation ratio in the rat was affected to a lesser extent. The neuropathy, it is suggested, is caused by raised S-adenosylhomocysteine levels in neural tissue; as a result, the methylation ratio is inverted and S-adenosylmethionine-dependent methylation reactions are inhibited.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1987

Solitary fibrous tumour of the pleura: an ultrastructural and immunohistochemical study.

Solitary fibrous tumour of the pleura is a benign neoplasm differing from diffuse pleural mesothelioma. It was originally thought to be a variant of mesothelioma because it consists of a spindle cell stroma associated with branching tubular structures lined by cuboidal cells. In this study of two cases the tubular structures were lined with ciliated and non-ciliated cuboidal cells. Ultrastructurally most of the non-ciliated cells had the features of type II pneumocytes, while the stromal cells had all the characteristics of fibroblasts. Immunohistochemical staining showed the epithelial cells to be positive for both keratin and carcinoembryonic antigen, whereas the stromal cells were negative. The findings support the theory that these tumours are fibroblastic in origin, and that the biphasic pattern is due to entrapment of non-neoplastic bronchiolar and alveolar epithelial cells.

Humans↗
PubMed1986

Ruptured adenomyotic cyst of the uterus--a case report.

The clinical and pathological features of an apparently unique case of an adenomyotic cyst of the uterus are reported. The cyst was located within the subserosal myometrium of a 39-year-old woman. Prior to hysterectomy, it had ruptured with bleeding into the peritoneal cavity. The differential diagnosis of myometrial cysts is briefly discussed.

Adult↗
PubMed1985

Undifferentiated (embryonal) sarcoma of the liver: ultrastructural and immunohistochemical similarities with malignant fibrous histiocytoma.

Two undifferentiated (embryonal) sarcomas of liver were studied ultrastructurally and immunohistochemically. Electron microscopic examination of the pleomorphic tumor cells revealed fibroblastic and histiocytic characteristics. There were no specific findings to support rhabdomyoblastic, leiomyoblastic, or epithelial differentiation. Cytoplasmic peroxidase-antiperoxidase (PAP) immunohistochemical staining for vimentin, alpha1-antitrypsin, and alpha1-antichymotrypsin was found. No staining for epidermal or internal organ cytokeratins, desmin, myoglobin, or alpha-fetoprotein was observed. The ultrastructural correlates of the cytoplasmic periodic acid-Schiff-positive, diastase-resistant hyaline globules were large, membrane-bound, heterogenous electron-dense inclusions, probably lysosomal in origin. These inclusions did not react on either alpha1-antitrypsin or alpha1-antichymotrypsin PAP staining. Tumor specimens from two metastatic sites were also examined. Neither contained the ducts or cysts that characterized the primary tumor. These studies confirm the mesenchymal nature of this uncommon childhood neoplasm and support the suggestion that the cytoplasmic hyaline globules represent a degenerative phenomenon. There are ultrastructural and immunohistochemical similarities with malignant fibrous histiocytoma.

Child↗
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

Hepatitis C among drug users: consensus guidelines on management in general practice.

BACKGROUND: Hepatitis C (HCV) is a common cause of morbidity among patients who attend general practitioners (GPs) in Ireland for methadone maintenance treatment. AIMS: To describe the development and content of guidelines for the management of HCV among current or former opiate users in the Eastern Regional Health Authority area attending GPs for methadone treatment. METHODS: The guidelines were produced in five stages: identification of key stakeholders; development of evidence-based draft guidelines; discussion of content; determination of 'Delphi'-facilitated consensus and review by a sample of GPs for whom the guidelines would be intended. RESULTS: The guidelines contain advice for GPs on all aspects of care of patients at risk of HCV, including general and preventative care, care of other bloodborne and hepatotoxic viruses, and the factors to be considered and appropriate evaluation prior to referring a patient for assessment at a hepatology unit. CONCLUSIONS: GPs have an important role to play in the care of patients at risk of, or infected with, HCV.

Adolescent↗
PubMedDate not supplied

Hepatitis C viral clearance in an intravenous drug-using cohort in the Dublin area.

BACKGROUND: The rate of spontaneous HCV viral clearance is reported as 20-25% but recent data indicate a higher frequency in some cohorts. The rate of spontaneous clearance in intravenous drug users has not been reported in an Irish setting. AIMS: To determine the rate of spontaneous hepatitis C viral clearance and genotype in an Irish intravenous drug-using cohort. METHODS: Drug users attending five drug treatment clinics in the Dublin were investigated. Data were prospectively recorded from January 1997 to June 2001 and follow-up testing completed in 2003. There were 496 HCV antibody positive patients identified and assessed for HCV RNA clearance. All were HIV and hepatitis B negative, 68.8% were male. RESULTS: HCV RNA negativity (viral clearance) was documented in 38% of patients. Viral clearance was 47.4% in females and 34.5% in males (p = 000.6). Clearance was independent of age or duration of intravenous drug use. Viral clearance as defined as two negative consecutive HCV RNA tests, a minimum of one year apart, was sustained in 82.2% at two-year follow-up, giving an overall viral clearance of 31.1%. HCV genotype 1 and 3 were most commonly identified at 48.8% and 48.5% respectively in those with chronic infection. CONCLUSIONS: Spontaneous HCV viral clearance occurs at a higher frequency than previously reported. Genotype 1 and 3 are commonest in the patient cohort.

Adult↗
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↗