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Biomedical subjects

M F Sullivan

Publications and source records attributed to M F Sullivan.

At least 19 recordsLinked to original sources
PubMed2001

Metoprolol attenuates postischemic depressed myocardial function in papillary muscles isolated from normal and postinfarction rat hearts.

The present study was designed to test the hypothesis that metoprolol treatment may enhance tolerance to ischemia in normal and postinfarction rat myocardium. Myocardial infarction was induced by permanent ligation of the left coronary artery in adult rats. Animals were divided into sham-operated and infarction groups with or without metoprolol treatment. Metoprolol treatment (60 mg/kg/day via gastric gavage) was started on the second day after surgery and continued until sacrifice at 6 weeks after myocardial infarction. Isometric force and intracellular Ca(2+) ([Ca(2+)](i)) transients were simultaneously recorded in isolated left ventricular papillary muscles. Ischemia was simulated by immersing the muscles into fluorocarbon with hypoxia. Metoprolol treatment induced a significant improvement of isometric force and ameliorated diastolic [Ca(2+)](i) overload in postinfarction rat myocardium at baseline. Metoprolol treatment also reduced diastolic [Ca(2+)](i), ameliorated the depression of developed tension during ischemia, and enhanced recovery of postischemic depressed myocardial function in sham-operated and postinfarction rat papillary muscles. Protein levels of the sarcoplasmic reticulum Ca(2+) ATPase of left ventricles and postischemic papillary muscles from metoprolol-treated rats were higher than those in placebo-treated animals. We concluded, therefore, that metoprolol treatment produced appreciable improvement of intracellular Ca(2+) handling during ischemia-reoxygenation cycles, and enhanced recovery of postischemic depressed myocardial function in both normal and postinfarction rat myocardium.

Adrenergic beta-Antagonists↗
PubMed1997

Survey of spinal therapeutic procedures in the United Kingdom.

The type and frequency of spinal therapeutic work being undertaken in the United Kingdom (UK) by clinicians with an interest in the surgical treatment of disorders of the spine (primary and secondary subspecialty interest) were evaluated by means of a postal questionnaire. The willingness of respondents to take part in postgraduate spinal training was determined along with issues regarding accessibility of spinal services to non-specialist physicians in the health service in the UK. The results of 450 respondents provided insight into the types of procedures taking place, for example: primary spinal decompression was regularly carried out by 76% of surgeons, while at least 20% of respondents regularly carried out 66% of the procedures surveyed. We found that 10% of surgeons indicated that they were prepared to participate actively in postgraduate spinal surgical training.

Education, Medical, Continuing↗
PubMed1991

The grieving process in cultural change.

A real sense of loss is experienced by many middle managers as hospitals change their cultures and evolve toward participatory management. To work through the loss involved, managers need time and resources to grieve for the old as they learn the new. Although the grieving process is relatively straightforward, difficulty arises because the need to talk and grieve for the old occurs precisely when all attention and effort focuses on the new. Administrative groups may feel threatened by middle management's expression of grief. Unwillingness to acknowledge and support that grief may provoke greater anger and resistance, increasing the problems associated with change. In the long run, time spent grieving for the old will make the transition to the new that much smoother. Organizations will see a positive return from time spent in the grieving process. Inability to let go of the old is often at the root of the uneasiness, resistance, and lack of visible commitment to the new. Why should we not spend the required time appreciating and then letting go of the old even as we teach the new? As we progress to the learning organization, to a staff empowered to resolve problems and seize opportunities, let it be known that expressions of the staff's humanity will be tolerated. Mistakes will be much more acceptable than lack of effort for fear of error. In working together, better patient care can be attained along with personal and organizational strength. Recognizing Annette's, or any manager's or staff member's, loss and allowing the grief necessary to resolve that loss will benefit all.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗
PubMed1988

Absorption of 233U, 237Np, 238Pu, 241Am and 244Cm from the gastrointestinal tracts of rats fed an iron-deficient diet.

Absorption of U, Np, Am and Cm was increased by factors of 3.4, 7.1, 2.7 and 1.7, respectively, when nitrate solutions of these actinides were gavaged to adult rats fed an iron-deficient diet. Retention increased proportionately in liver, kidney and carcass. The concentration of the actinides excreted also increased substantially (over that of controls) in the urine of iron-deficient rats gavaged with 233U and 237Np, but not in those with 241Am or 244Cm. Weanling rats on an iron-deficient diet, gavaged with ferric nitrate immediately before administration of 238Pu nitrate, retained between 4% and 12% of the 238Pu retained by litter mates that were not treated intragastrically with iron.

Americium↗
PubMed1987

Effect of excess Fe on Cd or Pb absorption by rats.

Absorption of cadmium and lead from the gastrointestinal (GI) tract of adult rats was measured after gavage with solutions of 109Cd or 210Pb. Before the radionuclide gavage, animals were either fed or fasted for 24 h, or fasted and given a supplemental gavage of ferric or ferrous iron. Fasting caused a slight increase in 109Cd absorption that was not statistically significant; ferrous iron caused a three-fold increase; and ferric iron increased absorption 14-fold. In contrast, fasting increased 210Pb absorption fivefold, and the oxidizing agents ferric iron and quinhydrone blocked the effect of fasting. Gavage of 8-d-old rats with 109Cd and either ferric or ferrous iron doubled the amount of cadmium retained in the carcass and substantially decreased the amount retained in the GI tract. Some of the large fraction (60-70%) of 109Cd stored in the mucosa of the intestine was absorbed into the body with time. An excess of ferric iron had an opposite effect on the retention of lead in the carcasses of 8-d-old rats, decreasing it from 53% of the gavaged dose to 3%; the effect on the amount retained in the intestine was similar, decreasing it from 16% to 8%. These results suggest that the mechanisms for transport of cadmium and iron across the intestine may be similar in the adult and neonatal rat, but that the oxidizing effect of ferric iron on cadmium absorption is much greater in the adult.

Animals↗
PubMed1987

The cost/benefit study: a competitive edge.

The well-executed cost/benefit study is a tool administrators can use effectively to gain a competitive edge. First, by identifying the tangible and the intangible benefits, the risks and the opportunities, the cost/benefit study provides information crucial to the decision-making process. Secondly, by developing an action plan for realizing benefits while controlling costs, the cost/benefit study helps administrators insure an optimum return on each of their investments. The results of this study not only help in the evaluation and justification of proposals, for new computer system, but can easily be incorporated into the evaluation process for new business ventures. An area often overlooked is the application of the cost/benefit study to the problem-resolution process. In identifying the constraints of the present system as well as the costs, the study helps administration pinpoint the causes of particular problems. In summary, the two principal deliverables from the cost/benefit study are the identification of benefits and the development of an action plan for realizing those benefits.

Cost-Benefit Analysis↗
PubMed1986

Clinical and necropsy observations early after simultaneous replacement of the mitral and aortic valves.

Clinical and necropsy findings are described in 54 patients, aged 25 to 83 years (mean 53), who died within 60 days of simultaneous replacements of both mitral and aortic valves. The patients were separated into 4 groups on the basis of the presence of stenosis (with or without associated regurgitation) or pure regurgitation of each valve: 30 patients (56%) had combined mitral and aortic valve stenosis; 12 patients (22%) had mitral stenosis and pure aortic regurgitation; 8 patients (15%) had pure regurgitation of both valves; and 4 patients (7%) had pure aortic regurgitation and mitral stenosis. Necropsy examination in the 54 patients disclosed a high frequency (48%) of anatomic evidence of interference to poppet or disc movement in either the mitral or aortic valve position or both. Anatomic evidence of interference to movement of a poppet or disc in the aortic valve position was twice as common as anatomic evidence of interference to poppet or disc movement in the mitral position. Interference to poppet movement is attributable to the prosthesis's being too large for the ascending aorta or left ventricular cavity in which it resided. The ascending aorta is infrequently enlarged in patients with combined mitral and aortic valve dysfunction irrespective of whether the aortic valve is stenotic or purely regurgitant. Likewise, the left ventricular cavity is usually not dilated in patients with combined mitral and aortic valve stenosis, the most common indication for replacement of both left-sided cardiac valves. Of the 54 patients, 12 (22%) had 1 mechanical and 1 bioprosthesis inserted. It is recommended that both substitute valves should be mechanical prostheses or both should be bioprostheses.

Adult↗
PubMed1986

Mitral valve stenosis and pure tricuspid valve regurgitation: comparison of necropsy patients having simultaneous mitral and tricuspid valve replacements with necropsy patients having simultaneous mitral valve replacement and tricuspid valve anuloplasty.

Clinical and morphologic observations are described in 30 patients (23 [77%] of whom were in functional class III or IV) who underwent replacement of the mitral valve for mitral stenosis and either simultaneous replacement (13 patients, group I) or anuloplasty (17 patients, group II) of the tricuspid valve for pure tricuspid valve regurgitation. Comparison of the 13 patients in group I with the 17 patients in group II disclosed similar mean ages (55 vs 58 years), similar average preoperative right ventricular systolic pressures (64 vs 61 mm Hg), similar average right atrial mean pressures (10 vs 9 mm Hg), similar average left ventricular systolic pressures (126 vs 120 mm Hg), similar average pulmonary artery wedge-left ventricular mean diastolic pressures (16 vs 18 mm Hg), similar cardiac indexes (2.1 vs 2.0 liters/min/m2), similar mean heart weights (507 vs 535 g), and similar percents with grossly visible foci of left ventricular necrosis (15% vs 12%) and fibrosis (23% vs 12%). Of the 13 patients in group I, 10 (77%) died early (less than or equal to 60 days of tricuspid valve replacement) and 3 (23%) died late (29, 37 and 120 months); of the 17 patients in group II, 14 (82%) died early and 3 (18%) died late (4, 9 and 98 months). The causes of early death in the 2 groups were different: of the 10 patients in group I who died early, the cause was excessive bleeding in 5, low cardiac output of undetermined etiology in 3, dysfunction of both prostheses in 1 and cerebral insult in 1; of the 14 patients in group II who died early, none died from excessive bleeding, 4 from decreased cardiac output of uncertain cause, 5 from left ventricular inflow obstruction (produced by a Starr-Edwards ball-valve prosthesis in 4 and from a Starr-Edwards disc prosthesis in 1), 1 from left ventricular outflow obstruction (by a porcine bioprosthesis), 2 from technical mishaps (incision into left ventricular free wall with rupture in 1 and ligation of the left circumflex coronary artery with resulting acute myocardial infarction in 1) and 2 died suddenly for reasons not determined. Of the 6 patients dying greater than 60 days after operation, 4 died from chronic congestive cardiac failure, 1 from a cerebral embolus and 1 from prosthetic valve endocarditis.

Adult↗
PubMed1986

Clinical and morphologic observations after simultaneous replacement of the tricuspid, mitral and aortic valves.

Clinical and morphologic observations are described in 12 patients who underwent simultaneous replacement of the tricuspid, mitral and aortic valves. All 12 patients had mitral stenosis, 10 aortic valve stenosis and 2 pure aortic valve regurgitation; 5 had tricuspid valve stenosis and 7 pure tricuspid valve regurgitation. Of the 10 patients who died within 60 days of triple valve replacement, 7 had the low cardiac output syndrome, which in 4, and possibly 5, of the 7 was attributed to prosthetic aortic valve stenosis. In none of the 12 patients was the ascending aorta dilated, and in the 4 (possibly 5) patients with low cardiac output, the space between the surface of the caged poppet (4 patients) or margins of the tilting disc (1 patient) in the aortic valve position and the aortic endothelium appeared inadequate to allow unobstructed flow despite small-sized prostheses in all but 1 patient. Thus, aortic valve replacement in the setting of triple valve dysfunction is hazardous or potentially so. The relative small sizes of the hearts in these patients also make valve replacement more difficult (and hazardous) compared to hearts with larger ventricles and aortas.

Adult↗
PubMed1986

Influence of iron on plutonium absorption by the adult and neonatal rat.

To determine how iron affects plutonium absorption, adult rats were gavaged with 238Pu nitrate (pH 2) after they had been fed an iron-deficient diet or treated with iron supplements. Neonatal rats born to dams on an iron-deficient diet were also gavaged with 238Pu. An iron-deficient diet resulted in enhanced 238Pu absorption both in the adults and in neonates born to iron-deficient dams. Ferric iron increased 238Pu absorption 12-fold in adult rats; injected iron-dextran reduced that increase; gavaged ferrous iron reduced 238Pu absorption to one-third of the control value. Rat neonates absorbed 30 to 40 times as much 238Pu as adults; absorption was lowered in groups that received iron supplements: Iron-dextran caused a 50% reduction; ferric iron, 95%; and ferrous iron, greater than 95%. The results demonstrate an effect of the oxidation state of iron on plutonium absorption in adult rats different from that observed in suckling rats. The results suggest that the high rate of 238Pu absorption by neonatal animals is due not only to the permeability of their intestines but also to their high demand for iron.

Animals↗
PubMed1986

Cell growth and hemoglobin synthesis in murine erythroleukemic cells propagated in high density microcapsule culture.

A new microencapsulation technology, developed for the encapsulation of living cells, has been demonstrated to be useful for the study of growth and differential gene expression using Friend erythroleukemic cells cultured at high cell densities. Using this technology, cultures of FL Clone 745 cells were encapsulated within semipermeable membranes composed of cross-linked alginic acid and poly-l-lysine. Cell growth studies measuring total cell number demonstrated an average generation time of 8.5 h in 5% (vol/vol) microcapsule cultures vs. 8.0 h in suspension cultures. Similar microcapsule cultures were serially propagated for more than 90 cell generations (13 sequential passages) with no significant change in this growth rate. In addition, final culture densities of greater than 1.0 X 10(8) cells/ml of intracapsular volume were attained using a 3% (vol/vol) microcapsule culture in conjunction with a standard refeeding schedule. Comparison of the level of dimethyl sulfoxide-induced hemoglobin production in suspension and microcapsule cultures demonstrated that the total amount of hemoglobin produced on a per cell basis was comparable in both systems. Due to the retention characteristics of the semipermeable membrane, the concentration of detergent-released hemoglobin, relative to other released protein, was approximately twofold higher in microcapsule cultures than in control suspension cultures.

Alginates↗
PubMed1986

Influence of oxidizing or reducing agents on gastrointestinal absorption of U, Pu, Am, Cm and Pm by rats.

Absorption of 233U, 238Pu, 241Am, and 244Cm from the gastrointestinal (GI) tract was measured in rats, fed ad libitum or fasted, that were gavaged with solutions containing ferric iron, ferrous iron, iron powder, quinhydrone or ascorbic acid. Absorption and retention of all of these actinides was increased substantially by fasting and by the addition of mild oxidizing agents, ferric iron and quinhydrone. In contrast, absorption and retention were decreased to below the fasted level by all the reducing agents except ascorbic acid, which caused diarrhea and an increase in absorption. Absorption of the lanthanide element 147Pm from the intestine of fasted rats was also increased by ferric iron. Some of these actinide elements are polyvalent and are, in some cases, known to be absorbed from the GI tract more readily in their higher oxidation states. This suggested an oxidation-reduction mechanism for the effect of fasting and the action of the chemical agents used. However, the improbability that either 241Am(III) 244Cm(III) or 147Pm is converted to a different oxidation state under these conditions makes that mechanism unlikely. Other explanations are suggested.

Actinoid Series Elements↗
PubMed1986

Effectiveness of DTPA therapy when administered intragastrically or intraperitoneally to remove Pu from adult or neonatal rats.

Adult and neonatal rats were given 238Pu by gavage or parenterally and treated with 0.5 mmoles/kg of calcium diethylenetriaminepentaacetate (DTPA), by gavage or parenterally, to determine its effectiveness for removing Pu. Parenteral administration of DTPA to adult rats 2 h after an intravenous 238Pu injection was much more effective than intragastric treatment, removing nearly 70% of the retained dose. When 238Pu was given to adults intragastrically (IG), followed by DTPA given either intraperitoneally (IP) or IG 2 h later, 238Pu absorption increased while retention remained either unchanged, or increased. When neonates were given 238Pu IG and treated 2 h later with intraperitoneal or intragastric DTPA, removal of 238Pu was better than in adults: more than 80% of the 238Pu that was absorbed and retained was removed by intragastric DTPA. When neonates were injected IP with 238Pu, treatment with intraperitoneal DTPA was more effective for 238Pu removal than intragastric treatment.

Absorption↗
PubMed1986

Neptunium-237 inhalation in rats.

Groups of rats were exposed to aerosols of 237Np nitrate to determine clearance rates, retention and distribution at various intervals after inhalation. Initial lung burdens (ILB) after 237Np inhalation by three treatment groups were 0.12, 0.19 and 0.37 mu Ci/kg, respectively. Radiochemical analyses of animals killed at 4, 8, 14, 28 and 90 d, as well as data for others maintained until they became moribund, showed that their lung clearance followed a three-compartment model, clearance half-times for which were 1, 35, and 10,000 d, respectively. Only 3% of the ILB was retained after 90 d; 12% of that burden had translocated to the skeleton at 750 d; the half-time for skeletal retention was 2500 d. A single tumor was the only malignancy detected in the lungs of the 35 animals allowed to survive the early phase of the study.

Administration, Inhalation↗
PubMed1986

Dome osteotomy of the tibia for osteoarthritis of the knee.

Proximal tibial osteotomy is commonly performed for osteoarthritis of the knee with deformity. The results of 105 dome osteotomies have been reviewed at a minimum follow-up of one year and an average of 4.8 years. Before operation all the knees were painful, 50.5% severely; a further 45.7% disturbed sleep at night. At review 15.2% of knees were free of pain and 60% had only slight pain which did not restrict activity. The preoperative range of movement was maintained and there was only a slight tendency for radiological changes to progress, with actual improvement in some cases. No correlation was found between the correction of deformity to physiological valgus and the result. We cannot explain why tibial osteotomy produces such useful and sustained pain relief.

Follow-Up Studies↗