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Biomedical subjects

S Armstrong

Publications and source records attributed to S Armstrong.

At least 19 recordsLinked to original sources
PubMed1992

Utilization of 1,3,5-trihydroxybenzene (phloroglucinol) by a soil isolate, Rhodococcus species BPG-8.

A Gram-positive bacterial strain was isolated from oil rich soil in Newfoundland and found to utilize various di- and trihydroxylated aromatic compounds as a source of carbon and energy. This bacterium exhibited rod/coccus dimorphism during its growth cycle. Chemical analysis of cell wall composition (amino acids, sugars, and fatty acids) was performed using gas chromatography-mass spectrophotometry and high pressure liquid chromatography. Comparison of both acid production and growth substrates showed complete homology with Rhodococcus erythropolis. Growth of the isolate on phloroglucinol (1,3,5 trihydroxybenzene) occurred in the pH range 5-8; with a substrate and temperature optima of 8.0 mM and 25 degrees C. The oxidation of PG was examined using whole cells as well as crude cell extracts. PG oxidation was shown to be due to an inducible enzyme system. Tentatively the isolate was identified as Rhodococcus species BPG-8 which is able to utilize phloroglucinol as the sole source of carbon and energy.

Acids↗
PubMed1992

Metabolism of gallate in Penicillium simplicissimum.

The pathway for the degradation of gallate (3,4,5-trihydroxybenzoate) by a new strain of Penicillium was examined by in vivo and in vitro cell-free systems. The organism was identified as P. simplicissimum (Oud) Thom. It grew optimally at pH 5.5 and 27 degrees C, with 11.75 mM (0.2%) gallate added to the basal salt media. Mycelia grown on gallate accumulated protocatechuate in the medium, and had inducible activity for protocatechuate 3,4-dioxygenase as determined by spectrophotometric and oxygen electrode studies. A NADPH-dependent reductase in the cell-free extract reduced gallate to dihydrogallate. Maleylacetate reductase was also detected in the gallate induced cell-free extract, while beta-ketoadipate was detected as the product produced. The possible steps in the degradation of gallate are discussed.

Gallic Acid↗
PubMed1992

Clinical and hemodynamic assessment of the Hancock II bioprosthesis.

The Hancock II bioprosthesis was used for heart valve replacement in 614 patients from 1982 to 1990. Aortic valve replacement (AVR) was performed in 376 patients, mitral valve replacement (MVR) in 195, and aortic and mitral valve replacement (DVR) in 43. The mean age was 62.7 years, and 78% of all patients were in New York Heart Association functional class III or IV before operation. Coronary artery bypass graft was necessary in 232 patients and replacement of ascending aorta in 55. There were 31 operative deaths (AVR, 4%; MVR, 6%; DVR, 9%). Follow-up was complete in 98.5% of the patients and extended from 12 to 103 months, with a mean of 49 months. At the last follow-up, 85% of the patients were in New York Heart Association class I or II. The actuarial survival at 8 years was 79% +/- 3% for AVR, 68% +/- 4% for MVR, and 65% +/- 10% for DVR. The freedom from stroke at 8 years was 93% +/- 2% for AVR, 83% +/- 5% for MVR, and 90% +/- 5% for DVR. At the end of 8 years 96% +/- 1% of all patients were free from endocarditis, 92% +/- 1% were free from primary tissue failure, and 89% +/- 3% were free from reoperation. The actuarial freedom from valve-related death at 8 years was 98% +/- 1% for AVR, 86% +/- 5% for MVR, and 91% +/- 6% for DVR. Hemodynamic assessment was obtained by Doppler echocardiography in all operative survivors and demonstrated satisfactorily effective valve orifices and transvalvular gradients. The clinical results obtained with the Hancock II bioprosthesis have been gratifying, particularly in the aortic position. This bioprosthesis is our biological valve of choice.

Actuarial Analysis↗
PubMed1992

Microwave warming of peritoneal dialysis fluid.

A nursing research study was undertaken to determine whether biochemical composition of peritoneal dialysate fluid was altered with microwave heating and whether the external bag temperature of the heated dialysate was a reliable reflection of the actual fluid temperature. No significant laboratory changes were found in the control, heated, or superheated solutions. By closely following established time frames for specific bag solution volume, agitation of fluid prior to instillation, and external temperature check with specific minimum and maximum acceptable temperatures, peritoneal dialysate can be microwaved and used safely.

Clinical Nursing Research↗
PubMed1992

Breath-actuated inhalers in chronic asthma: comparison of Diskhaler and Turbohaler for delivery of beta-agonists.

An open, randomized, cross-over study was performed to compare the efficacy and acceptability of two breath-actuated inhalers, the Turbohaler (T) and Diskhaler (D), for delivery of beta-agonists. Thirty six adults with chronic asthma requiring beta-agonists four times daily were treated with terbutaline 500 micrograms via T and salbutamol 400 micrograms via D four times daily, each period lasting four weeks. Additional bronchodilator via pressurized aerosol was permitted as required. Peak expiratory flow (PEF) was recorded in the morning (before and after beta-agonist) and in the evening. The mean morning PEF was higher during the first two weeks using T (295 l.min-1) than whilst using D (281 l.min-1, p < 0.01), but this difference did not persist during the second two weeks and there were no differences in post-bronchodilator PEF or rescue beta-agonist use. After four weeks, > 90% of patients used both inhaler devices efficiently and they were equally acceptable in terms of ease of use and convenience to carry. The Diskhaler and Turbohaler achieve similar clinical efficacy for delivery of beta-agonists.

Administration, Inhalation↗
PubMed1991

The cost of nursing excellence in critical care.

The results of the American Association of Critical-Care Nurses Demonstration Project support the contention that high quality critical care nursing can be provided to patients at a reasonable cost. In addition, the data refute the notion that elements influenced by nurses--supplies and nursing care--are the most costly portion of the total hospital charge.

Costs and Cost Analysis↗
PubMed1990

Fate of patients undergoing transluminal angioplasty for lower-limb ischemia.

A prospective study of 370 patients who underwent 500 percutaneous transluminal angioplasties (PTAs) for lower-limb ischemia over a 7-year period was performed. A 97% follow-up rate was achieved. The first PTA was successful in 188 patients (51%). Of the failures, 31% were failed attempts at dilation and 73% occurred within 1 month of intervention. Of the patients with failed PTA, 39% underwent bypass surgery and 24% underwent amputation. The 30-day mortality rate was 3%, with 1% of the deaths attributed to PTA. The survival rate at 5 years for the successes was double that for the failures (P less than .0005). The best results were in femoropopliteal stenoses with two or three patent calf vessels (cumulative patency rate, 78% at 3 years) and the worst in femoropopliteal occlusions with one or no patent calf vessels (cumulative patency rate, 25% at 3 years). Log rank tests on the life-table data were used to show factors favoring a good outcome. It is concluded that PTA is the treatment of first choice in suitable patients and, although the failure of intervention in critical ischemia has a significant risk, it is a valuable addition to the therapeutic options in patients with little chance of surgical treatment.

Adult↗
PubMed1989

American Association of Critical-Care Nurses Demonstration Project: profile of excellence in critical care nursing.

The American Association of Critical-Care Nurses developed a Demonstration Project to document fiscal costs and patient care effectiveness of critical care nursing in a unit characterized by valued organizational attributes. Data were collected by interview, observation, and written surveys from 42 nurses, 68 physicians, and 192 patient admissions. Decentralized administration, participatory management, high rate of CCRN certification, all-registered nurse staff, and high nurse-physician collaboration were present. Organizational and clinical outcomes were positive: high satisfaction, low turnover, low mortality ratio, no new complications, high patient satisfaction. The proportion of charges for nursing-controlled factors was low compared with proportion of total stay spent in the unit. Aspects of structure, process, and outcome can be measured simultaneously in critical care; these measurements indicate that positive organizational and clinical outcomes coexist with valued aspects of the organizational environment.

Costs and Cost Analysis↗
PubMed1989

American Association of Critical-Care Nurses demonstration project: patients' recollections of critical care.

Although more patients are surviving illness that requires critical care, little is known about the impact of the critical care experience on patients as they recall it. In this study we describe 59 patients' recollections of the critical care experience within 24 to 48 hours after transfer from the unit. Responding to an open-ended series of questions, patients accurately identified why they were admitted to critical care units. Actions related to observations, technical care, alleviation of concerns, and self-care promotion were recalled by patients. Nurses were the persons most frequently associated with such actions. In contrast, physicians were most frequently cited as the source of information about their health condition. Almost half of the patients who were willing and able to be interviewed described the impact of the experience as positive or neutral. Pain and sleeplessness were the major problems identified by patients.

Critical Care↗
PubMed1988

Developmental intervention program for high-risk premature infants: effects on development and parent-infant interactions.

Developmental follow-up studies have documented that low birth weight infants are at high risk for mental and physical disabilities, despite recent advances in neonatal intensive care. Moreover, parent-infant bonding is hampered by the barriers created by technical equipment. This study evaluated a program of hospital and home-based developmental interventions designed to enhance the development of high-risk, preterm infants and the quality of communication between infants and their caregivers. Treatment and contrast groups consisted of 41 premature infants weighing less than 1800 g at birth. Treatment took a preventive approach, consisting of daily multimodal interventions in-hospital and twice-monthly interventions by child development specialists in the child's home, through 12 months adjusted age. Infants in the contrast group received traditional, remedially oriented care. The Bayley Scales of Infant Development were used to measure mental and psychomotor development, and the Greenspan-Lieberman Observations System (GLOS) was used to analyze the behavioral characteristics of infant-caregiver interactions. Developmental interventions had positive, significant effects on mental development and on the quality of caregiver-infant interactions. Changes in mental development were not independent of changes in the GLOS.

Cognition↗
PubMed1986

Specific thromboxane synthetase inhibition and retinopathy in insulin-dependent diabetics.

We have previously reported that specific thromboxane synthetase inhibition may be associated with a reduction in albumin excretion rate in insulin-dependent diabetics (IDD). We now report studies of retinal morphology assessed by serial fluorescein angiography in 25 insulin-dependent diabetics during a 16-week double-blind, randomized, placebo-controlled study of the specific thromboxane synthetase inhibitor UK-38,485. Assessment of angiograms was by, computerized image analysis indicating the percentage area of vascularization and, panel scoring by 4 ophthalmologists who scored the posterior pole in each of the 4 angiograms "blind" according to a prearranged system. There was no significant change in percentage area of vascularization in either placebo or "active" group during the study. Panel scoring, however, suggested that some patients deteriorated whilst others remained unchanged or improved. There was, however, no significant difference in these parameters between those subjects on UK-38,485 and those on placebo. We conclude that specific thromboxane synthetase inhibition is not associated with any significant change in diabetic retinopathy over a 4-month period of study.

Adult↗
PubMed1985

Human monocyte recognition of complement-coated lymphoblastoid cells.

The macrophage system in man plays a significant role in the detection of foreign cells. The mechanisms by which macrophages recognize malignant cells, however, are not well understood. We used human monocytes and four lymphoblastoid cell (LC) lines derived from human acute lymphocytic leukemia to investigate the initial recognition of tumor cells by monocytes. IgM antibody mediated the binding of these cells to monocytes only in the presence of complement. The stepwise addition of complement components to IgM-coated LC indicated that C3 was necessary to monocyte binding. Similarly, monocyte recognition of IgM-coated LC was maximal in the presence of sera from patients with congenital C5 or C6 deficiency, but absent in the presence of sera deficient C4 or from a patient with congenital C2 deficiency. Complement activation was associated with C3 consumption and the deposition of substantial amounts of C3 on to LC. Although 3H-C3 bound to LC appeared stable for 2 hours, approximately 4.0 +/- 2 X 10(5) 3H-C3 per LC was necessary for monocyte recognition, compared to approximately 2.7 +/- 0.5 X 10(3) 3H-C3 per RBC. The data indicate that LC can be recognized by monocytes through complement by mechanisms similar to nonmalignant target cells. However, substantial amounts of C3 are necessary to induce monocyte recognition of IgM-coated LC and, thus, such complement mediated recognition may be inefficient.

Cell Communication↗