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Biomedical subjects

M Cahill

Publications and source records attributed to M Cahill.

At least 37 records · Page 2Linked to original sources
PubMed1999

Isolation, characterization, and biological activity of naphthoquinones from Calceolaria andina L.

Two compounds recognized as responsible for the insecticidal activity of extracts of Calceolaria andina L. (Scrophulariaceae) have been isolated and characterized as 2-(1, 1-dimethylprop-2-enyl)-3-hydroxy-1,4-naphthoquinone and the corresponding acetate, 2-acetoxy-3-(1,1-dimethylprop-2-enyl)-1, 4-naphthoquinone. Their activities against 29 pest species and 9 beneficial species of arthropod from a total of 11 orders have been determined. Activities against homopteran and acarine species are of the same order as those of established pesticides, and, significantly, no cross-resistance is observed for strains resistant to established classes of insecticide. Mammalian toxicities are low.

Animals↗
PubMed1999

Coats' disease of the retina (unilateral retinal telangiectasis) caused by somatic mutation in the NDP gene: a role for norrin in retinal angiogenesis.

Coats' disease is characterized by abnormal retinal vascular development (so-called 'retinal telangiectasis') which results in massive intraretinal and subretinal lipid accumulation (exudative retinal detachment). The classical form of Coats' disease is almost invariably isolated, unilateral and seen in males. A female with a unilateral variant of Coats' disease gave birth to a son affected by Norrie disease. Both carried a missense mutation within the NDP gene on chromosome Xp11.2. Subsequently analysis of the retinas of nine enucleated eyes from males with Coats' disease demonstrated in one a somatic mutation in the NDP gene which was not present within non-retinal tissue. We suggest that Coats' telangiectasis is secondary to somatic mutation in the NDP gene which results in a deficiency of norrin (the protein product of the NDP gene) within the developing retina. This supports recent observations that the protein is critical for normal retinal vasculogenesis.

Amino Acid Substitution↗
PubMed1999

Ocular adnexal lymphoma-comparison of MALT lymphoma with other histological types.

AIMS: To correlate histological features of ocular adnexal lymphoma using the revised European American lymphoma classification (REAL), with stage of disease at presentation, treatment modalities, and patient outcome. MALT lymphoma defines an extranodal marginal zone B cell lymphoma as outlined in the REAL classification. Comparison groups of patients included those with primary ocular adnexal MALT lymphoma versus primary ocular adnexal lymphomas of other types, MALT lymphoma versus non-MALT lymphomas (primary and secondary), and primary ocular adnexal lymphoma (MALT lymphomas and other types) versus secondary ocular adnexal lymphomas. METHODS: A retrospective review of the National Ophthalmic Pathology Laboratory records identified 20 cases of ocular adnexal lymphoma over a 10 year period which were reclassified using appropriate immunohistochemical stains. Patients' medical records were examined for data including stage of the disease at presentation, mode of treatment, and patient outcome. RESULTS: Among the 20 cases identified 14 had primary ocular adnexal lymphomas. 10 of the primary lymphomas had histological features of MALT lymphoma. One case was a primary ocular adnexal T cell lymphoma, one a follicular centre, follicular B cell lymphoma, and two were large cell B cell lymphomas. Six cases had systemic disease, four large B cell, one follicular centre, follicular B cell, and one mantle cell. A significantly higher proportion of patients with MALT lymphomas had early disease (p = 0.005), initially required local treatment (p = 0.005) and were alive at last follow up (p = 0.001) than those without. Two patients with MALT lymphoma had recurrence of lymphoma which responded to further treatment. CONCLUSIONS: Patients with primary ocular adnexal MALT lymphomas present with localised disease requiring local treatment and have a better outcome compared with patients with other types. As a small percentage of these tumours recur, patients should be followed up indefinitely.

Adult↗
PubMed1998

The use of clinical logs to improve nursing students' metacognition: a pilot study.

The purpose of this study was to examine the effectiveness of the use of a reflective clinical log to improve students' thinking strategies and metacognition (cognitive awareness). Rather than prepare a written nursing care plan prior to entering the clinical setting, students instead were asked to write in a clinical log at the completion of their clinical day, reflecting upon client problems that they had identified, the data that were used to identify these problems, the nursing interventions that were used, and the results of these interventions. The students reported that they preferred the use of a reflective log over writing nursing care plans and they felt that the logs improved their ability to think about their thinking (i.e. their metacognition). The results of this pilot study indicate that reflection in clinical logs assists students to become more active learners, to manage their own thinking, and to improve their metacognition. Additional research in this area is needed to confirm study findings and to provide further understanding regarding the effectiveness of clinical logs as a teaching strategy to improve students' metacognition.

Cognition↗
PubMed1998

Assessing the value of a new pharmaceutical. A feasibility study of contingent valuation in managed care.

OBJECTIVES: The authors assessed the feasibility and construct validity of the contingent valuation method for measuring the monetary value to healthy enrollees in a health maintenance organization of a new drug, filgrastim, as prophylaxis against febrile neutropenia after chemotherapy treatment for cancer. METHODS: A random sample of 220 enrollees from a closed-panel staff-model health maintenance organization who did not have cancer were interviewed. Chemotherapy, febrile neutropenia and filgrastim were described by video and decision board. Questions were asked in two different scenarios: (1) User-based: Assuming they were at the point of consumption and about to receive chemotherapy, what is the maximum they would be willing to pay to receive filgrastim? and (2) Insurance-based: Given they were at risk of cancer in the future, what is the maximum they would be willing to pay in additional monthly insurance premiums to add filgrastim to the plan? In a second insurance scenario where respondents were told that filgrastim was covered, what is the minimum reduction in premium that persons were willing to accept to relinquish coverage of the drug? A 2 x 2 factorial design was used to contrast two bidding algorithms to test for starting point bias and two 5-yearly prior risks of cancer, 1/200 versus 1/100. Main effects were tested by ANCOVA controlling for age, sex, health, and income. RESULTS: Demographics of experimental cells were similar. No evidence was found of significant starting point bias. For user-based questions, as expected, willingness-to-pay increases with febrile neutropenia risk reduction, but at a declining marginal rate. Despite careful presentation of information to respondents, willingness-to-pay for insurance was higher in the lower prior risk group. Consistent with previous contingent valuation studies, the authors of the present study found evidence that willingness-to-accept exceeds willingness-to-pay for coverage of the same benefit. CONCLUSIONS: An insurance-based contingent valuation study is feasible in a health maintenance organization. Construct validation evidence was encouraging, with the exception of the test for prior risk of cancer; however, this was a between-person contrast and may have been confounded by other factors.

Adult↗
PubMed1997

Prevalence of diabetic retinopathy in patients with diabetes mellitus diagnosed after the age of 70 years.

AIMS/BACKGROUND: A hospital based prevalence study was undertaken to estimate the prevalence of diabetic retinopathy (DR) in patients diagnosed as having diabetes mellitus after the age of 70 years. The prevalence of visually threatening retinopathy at the time of diagnosis of diabetes was also determined. The association between prevalence of DR and duration of diabetes mellitus, mode of treatment, HbA1c levels, presence of hypertension, and sex of patient was examined and a comparison was drawn between this study and earlier prevalence studies of DR in older type II diabetics. METHODS: Using data on the Irish Diabetic Retinopathy Register located in the Mater Misericordiae Hospital, Dublin, all patients who were diagnosed as having type II diabetes mellitus after the age of 70 years were invited to attend for ophthalmic review. Medical records were examined to determine the duration of diabetes mellitus, mode of treatment, recent HbA1c levels, and the presence of systemic hypertension. RESULTS: Of the 150 patients examined, 21 (14%) had some form of DR and 10 of these patients (6.6%) had visually threatening retinopathy or previously treated visually threatening retinopathy. Five patients (3.3%) presented with visually threatening retinopathy at the time of diagnosis of diabetes. Those patients with DR had a significantly higher median duration of diabetes (5.0 years) compared with those patients without DR (3.5 years). A significantly higher proportion of patients with DR required treatment with insulin and a correspondingly lower proportion of patients without DR were controlled on diet alone. There was no significant association between prevalence of DR and HbA1c levels, systemic hypertension, or sex of patient. There was a lower overall prevalence of DR in comparison with earlier studies. CONCLUSIONS: The prevalence of DR in these elderly type II diabetics is lower than than previously reported in patients with type II disease but a small percentage of patients had visually threatening retinopathy at presentation. Longer duration of diabetes and insulin use were associated with a significantly increased prevalence of DR. All elderly type II diabetic patients require thorough ophthalmic examination near to the time of first presentation and thereafter at regular intervals.

Aged↗
PubMed1996

Hematologic problems in pediatric patients.

OBJECTIVE: To provide a review of the common hematologic disorders of childhood: iron deficiency anemia, aplastic anemia, sickle cell disease, and hemophilia. DATA SOURCES: Review articles and book chapters pertaining to the care and treatment of children with hematologic disorders. CONCLUSIONS: These common hematologic disorders of childhood have the potential to cause not only acute illness but chronic medical problems, particularly in the growing child. Anticipating and preventing the long-term effects of the illness and treatment are the primary goals of care. IMPLICATIONS FOR NURSING PRACTICE: Nursing assessment, patient education, and long-term follow-up are major factors in the care of children with hematologic disorders. Nurse-managed comprehensive care clinics have provided successful programs directed at acute care and maintenance care for these children and their families.

Anemia, Aplastic↗
PubMed1996

Chrysiogenes arsenatis gen. nov., sp. nov., a new arsenate-respiring bacterium isolated from gold mine wastewater.

A new strictly anaerobic bacterium (strain BAL-1T) has been isolated from a reed bed at Ballarat Goldfields in Australia. The organism grew by reducing arsenate [As(V)] to arsenite [As(III)], using acetate as the electron donor and carbon source; acetate alone did not support growth. When BAL-1T was grown with arsenate as the terminal electron acceptor, acetate could be replaced by pyruvate, L- and D-lactate, succinate, malate, and fumarate but not by H2, formate, citrate, glutamate, other amino acids, sugars, or benzoate. When acetate was the electron donor, arsenate could be replaced by nitrate or nitrite but not by sulfate, thiosulfate, or iron oxide. Nitrate was reduced to ammonia via nitrite. The doubling time for growth on acetate (5 mM) plus arsenate (5 mM) or nitrate (5 mM) was 4 h. The G+C content of the DNA is 49 mol%. The 16S rRNA sequence data for the organism support the hypothesis that this organism is phylogenetically unique and at present is the first representative of a new deeply branching lineage of the Bacteria. This organism is described as Chrysiogenes arsenatis gen. nov., sp. nov.

Arsenates↗
PubMed1996

Anatomy of the extraneural blood supply to the intracranial oculomotor nerve.

AIMS: An anatomical study was undertaken to determine the extraneural blood supply to the intracranial oculomotor nerve. METHODS: Human tissue blocks containing brainstem, cranial nerves II-VI, body of sphenoid, and associated cavernous sinuses were obtained, injected with contrast material, and dissected using a stereoscopic microscope. RESULTS: Eleven oculomotor nerves were dissected, the intracranial part being divided into proximal, middle, and distal (intracavernous) parts. The proximal part of the intracranial oculomotor nerve received extraneural nutrient arterioles from thalamoperforating arteries in all specimens and in six nerves this blood supply was supplemented by branches from other brainstem vessels. Four nerves were seen to be penetrated by branches of brainstem vessels and these penetrating arteries also supplied nutrient arterioles. The middle part of the intracranial oculomotor nerve did not receive nutrient arterioles from adjacent arteries. The distal part of the intracranial oculomotor nerve received nutrient arterioles from the inferior cavernous sinus artery in all 11 nerves and in seven nerves this was supplemented by a tentorial artery arising from the meningohypophyseal trunk. The inferior hypophyseal artery arose from the meningohypophyseal trunk in all 11 cavernous sinuses dissected. CONCLUSION: This study shows a constant pattern to the blood supply of the intracranial oculomotor nerve. It also highlights the close relation between the blood supplies to the intracavernous oculomotor nerve and the pituitary gland.

Arteries↗
PubMed1995

Biochemical identification of interbreeding between B-type and non B-type strains of the tobacco whitefly Bemisia tabaci.

Polyacrylamide gel electrophoresis and a kinetic microplate assay were used to detect heterozygotes resulting from a cross between B-type and non B-type strains of the whitefly Bemisia tabaci. Both strains were homozygous for different esterase and acetylcholinesterase (AChE) enzymes, and heterozygotes were produced in one of two crosses between B-type females (diploid) and non B-type males (haploid). In reciprocal crosses, however, no female offspring were produced, indicating that fertilization had not occurred. Despite the identification of individuals heterozygous for the esterase and AChE markers, there was clearly a significant degree of reproductive incompatibility between the two strains. The biochemical assays provided a vital component of this study and the advantages of their use are discussed.

Animals↗
PubMed1995

The haemodynamic effect of prophylactic peri-operative dopexamine in coronary artery bypass patients.

Twenty-three low risk coronary artery bypass graft patients underwent a controlled study of the effects of prophylactic perioperative dopexamine hydrochloride on haemodynamic indices and peripheral perfusion. The infusion commenced following induction of anaesthesia and continued for 24 h postoperatively. The study demonstrated that dopexamine significantly increased cardiac index compared with the control group (P < 0.05) and that this effect was mediated through an increase in both left ventricular stroke volume index and heart rate (P < 0.05). This was associated with a significantly lower systemic vascular resistance (P < 0.05), without an increase in left ventricular stroke work index in the dopexamine group. Despite normal pre-operative left ventricular function, both groups exhibited a fall in pH (P < 0.05) relative to baseline levels. This fall in pH began prior to cardiopulmonary bypass and persisted in the early postoperative period in both groups, suggestive of tissue hypoperfusion and oxygen deficiency. These indices normalized more rapidly in the dopexamine group, suggesting a more rapid reversal of an intra-operative oxygen debt in this group. The study demonstrates the mechanism of action of dopexamine on cardiac function and peripheral perfusion during cardiac surgery and shows that the inodilator properties during cardiac surgery are useful haemodynamically and facilitate early reversal of tissue hypoperfusion and oxygen debt in this environment.

Adult↗
PubMed1993

The opioid receptor binding of dezocine, morphine, fentanyl, butorphanol and nalbuphine.

The ability of morphine, fentanyl, butorphanol, nalbuphine, and dezocine to compete with radiolabeled ligands for binding at the mu1, mu2, kappa1, and delta opioid receptors and the sigma receptor was characterized. In the absence of sodium, the potency of opioid receptor competition at each receptor site was found to be: mu1-fentanyl > butorphanol > morphine > or = dezocine = nalbuphine; mu2-butorphanol > fentanyl > nalbuphine > morphine = dezocine; kappa1-butorphanol > nalbuphine >> morphine > or = dezocine > fentanyl; and delta-butorphanol > nalbuphine > or = dezocine > morphine > fentanyl. For all five compounds, competition at the sigma receptor was weak, with nalbuphine and dezocine having Kis of approximately 0.5 microM and the other opioids having Kis of greater than 1 microM. Since the presence of 100 mM NaCl during the competitive binding decreased the K(i), to varying degrees, of all five opioids at the mu1 and delta receptors and of some of the opioids at the mu2 and kappa1 receptors, the five compounds studied appear to differ in efficacy at the five receptor sites.

Analgesics, Opioid↗