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Biomedical subjects

J M Ryan

Publications and source records attributed to J M Ryan.

At least 109 records · Page 6Linked to original sources
PubMed1984

Prevalence of high-risk thallium-201 scintigraphic findings in left main coronary artery stenosis: comparison with patients with multiple- and single-vessel coronary artery disease.

To determine the prevalence of high-risk thallium-201 (Tl-201) scintigraphic findings in patients with left main (LM) coronary artery disease (CAD), quantitative exercise Tl-201 scintigrams were analyzed in 295 consecutive patients with angiographic (greater than or equal to 50% stenosis) CAD, of which 43 (14%) had greater than or equal to 50% LM stenosis. A high-risk scintigram was defined as one that demonstrated (1) a LMCAD scintigraphic pattern (greater than or equal to 25% homogeneous decrease in Tl-201 activity in the middle and upper septal and posterolateral walls on the 45 degree left anterior oblique projection); (2) abnormal Tl-201 uptake or washout in multiple vascular scan segments indicative of multivessel disease; and (3) increased lung Tl-201 uptake on the initial anterior projection image. Of the 43 patients with LMCAD, 41 (95%) had an abnormal scintigram. Thirty-three (77%) had 1 or more high-risk scintigraphic findings, including 29 (67%) with a multivessel CAD scan pattern, of which 6 (14%) demonstrated a typical LMCAD pattern; and 18 (42%) with abnormal lung Tl-201 uptake. The prevalence of a high-risk scintigram in patients with LMCAD was significantly greater than that in 53 patients with 3-vessel disease (58%) (p = 0.05), 99 patients with 2-vessel disease (60%) (p = 0.04) and 100 patients with 1-vessel disease (41%) (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Reporting the patterns of local medical practices with cancer patients to community hospital physicians: the methodology.

This is a presentation of the methods chosen to present initial data to the physician site committees in the Minneapolis-West Metro Community Hospital Cancer Program. This data will be presented at approximately six-month intervals so that guidelines can be modified, to maximize the effectiveness of the physician management guidelines. The reporting system has been designed to allow each hospital to look at its own data as compared to the aggregate total of all the hospitals (but never another individual hospital), and to allow more detailed studies within a local hospital using the usual quality assurance procedures. The goal is to help in meeting the American College of Surgeons requirement of accredited cancer programs of continued surveillance of the cancer treatment given and the results in hospitals, and to document the effect of the Community Hospital Cancer Program upon cancer patient management.

Computers↗
PubMed1984

Evaluation of professional nursing practices in a community hospital cancer program: the methodology.

In summary, this evaluation plan is designed to assess current oncology nursing practices in a community setting. The focus of the plan is on patient problems identified in the CHCP Cancer Nursing Guidelines and the Hospice Nursing Guidelines. Critical decisions regarding which patient problems to focus on and the implementation of the evaluation plan remain with the CHCP committees. Technical assistance is provided by a CHCP Evaluation Specialist. Finally, summary reports will be generated at regular intervals so as to maximize the impact on current program development. There are several implications for this nursing evaluation plan, both immediate and long range. In the immediate, we hope that the results will help CHCP committees and individual hospitals make informed decisions about future program development. More importantly perhaps, we are for the first time in our local community identifying services central to nursing and developing base line data on the frequency of the delivery of these services. Looking into the future, we see additional implications for these studies. Currently, our evaluation system is a paper system, and paper systems are by their very nature time consuming and somewhat awkward. It is our hope that in the future information about nursing services will be registered on a computerized information system. Then, reports about the types of nursing services and amount of time spend with cancer patients could be automatically generated on a weekly basis, if so desired. However, if we are to attain this goal, we need to systematically identify common patient problems central to oncology nursing care that can be documented and studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospitals, Community↗
PubMed1984

The Falklands war--triage.

In order to provide first class treatment for casualties in the recent Falklands war it was necessary to apply rigid rules. Those who required treatment most urgently received earlier resuscitative and surgical care to give the best possible chance of good quality survival. The concept of Triage was applied at every level of medical care but was found to be most crucial at surgical centres. The dynamic nature of the Triage system was noted. Patients required constant reassessment and updating by experienced well trained teams. The system worked well. The success in employing resuscitation trained dental officers in the Triage role was particularly worth noting.

Atlantic Islands↗
PubMed1983

Mitral valve prolapse syndrome: analysis of 62 patients aged 60 years and older.

Sixty-two patients diagnosed as having mitral valve prolapse, 60 to 81 years old, presented with disabling chest pain (20), symptoms of arrhythmias including palpitations and syncope (16), or mitral regurgitation (MR) with symptoms of congestive heart failure (26). The diagnosis of MVP was made on the basis of a combination of classic auscultatory, echocardiographic and angiographic findings. Thirteen of the 20 patients with chest pain had normal coronary angiograms and 7 had significant coronary artery disease (CAD). Patients with CAD could not be differentiated by clinical presentation alone. Furthermore, the incidence and types of arrhythmias, the presence of a positive stress test, and hemodynamic findings were similar in all patients in this group whether or not CAD was present. The 16 patients with palpitations had a broad spectrum of rhythm disorders, including both supraventricular and ventricular arrhythmias. Two patients had prehospital "sudden death" and 2 others had systemic emboli. Twenty-one of the 26 patients with MR had valve surgery. Intraoperatively the valves were described as enlarged, floppy and with redundant leaflets. Histologic examination showed extensive "myxomatous" changes throughout the valve leaflets. Thus, mitral valve prolapse is a cause of symptomatic heart disease in the elderly. It has a predictable pattern of clinical presentation and should be considered in the differential diagnosis of older patients with disabling chest pain and arrhythmias and as the cause of progressive or severe MR.

Aged↗
PubMed1983

Intraoperative coronary artery spasm successfully treated with nitroglycerin and nifedipine.

Coronary artery spasm is recognized as a major cause of angina and may coexist with fixed coronary artery disease. This report presents the case of a patient who developed recurrent coronary artery spasm in the operating room following effective coronary artery bypass grafting. The coronary artery spasm was manifested by sudden ST segment elevation, hypotension, and decreased cardiac output. Direct injection of nitroglycerin into each coronary artery graft was necessary to reverse the coronary artery spasm. Peripheral intravenous nitroglycerin plus nifedipine administered through a nasogastric tube prevented further recurrence of coronary artery spasm.

Angina Pectoris↗
PubMed1983

Progressive extreme biatrial enlargement following mitral valve replacement.

Patients with mitral valve disease and extreme enlargement of the left atrium usually exhibit significant decrease in chamber size following corrective mitral valve surgery. We describe a patient in whom extreme right and left atrial enlargement developed, and progressed following mitral valve replacement, with no evidence of prosthetic valve malfunction or tricuspid valve disease.

Aged↗
PubMed1983

The Falklands war: Army field surgical experience.

In the recent Falklands campaign four Army Field Surgical Teams were deployed in the two phases of the war. They functioned as Advanced Surgical Centres and operated on 233 casualties. There were 3 deaths. The patterns of wounding and the methods of casualty management are discussed and compared with other recent campaigns.

Adult↗
PubMed1983

Renal and extrarenal production of erythropoietin following exchange transfusion with plasma or a perfluorocarbon-polyol.

The extrarenal production of erythropoietin (Ep) was measured in young adolescent rats following exchange-transfusion with normal rat plasma or the whole blood replacement fluid, Fluosol-43. In the plasma-transfused anephric groups, the peak extrarenal Ep response to the severe degree of anemic hypoxia represented 23% of that evoked in renal-intact groups. In contrast, the peak extrarenal production of Ep in Fluosol-transfused renoprival groups was almost equal to those serum Ep levels produced in renal-intact groups. Histological studies revealed significant fluorocarbon uptake by hepatic macrophages that coincided with the time of peak production of Ep. Thus, while intense levels of hypoxia are required to stimulate the extrarenal production of Ep, these data suggest that as Fluosol-43 is taken up by the hepatic macrophages, Ep production by these cells is stimulated.

Animals↗
PubMed1983

Proximal gastric vagotomy: a district general hospital experience.

A district general hospital experience with proximal gastric vagotomy over a nine-year period is reported. One hundred and eight patients undergoing the operation for chronic duodenal ulcer were assessed. The follow-up period was 1-9 years (mean 4 years and 7 months). The results were graded using a modification of the classification of Visick (1948). Over 85% of our patients were satisfied with their results. (Visick 1 and 2). Recurrent ulceration was noted in 3.9% of our series (4 cases). There were no deaths and few complications. The technique used by us is described briefly and the role of proximal gastric vagotomy in a district general hospital is discussed.

Adult↗
PubMed1982

The effects of division rate-limiting amounts of fetal bovine serum on the proliferation and aging of cultured chick cells.

Chick embryo fibroblasts serially propagated in media containing division rate-limiting amounts of fetal bovine serum underwent premature culture senescence as illustrated by accelerated declines in the number of cells incorporating 3H-thymidine, increased population doubling times, reduced cell densities at subcultivation, and reduced replicative life-spans compared to cells grown in medium containing non-rate-limiting amounts of serum. Low serum serially propagated "senescent" cultures returned to 10% serum containing medium had proliferative rates, incorporated 3H-thymidine, and attained saturation densities at confluency similar to younger cells. "Senescent" cells serially propagated in low serum and returned to 10% serum, achieved life-spans similar to cells continuously grown in the presence of 10% serum. The results of these and other studies show that cells serially propagated in the presence of division rate-limiting amounts of fetal bovine serum, or at high inoculation densities, accumulate a substantial number of cells in the population during exponential growth conditions that are not senescent but are prevented from entering DNA synthesis because of mitogen limitations. Our results indicate that the amount of serum mitogen in the growth medium affects only the rate at which cells express their genetically predetermined replicative potential and not the replicative life-span per se. These results are discussed in relation to the techniques that should be employed for studying cellular aging and the mechanism of senescent cell formation.

Aging↗
PubMed1981

Cumulative population doublings as the determinant of chick cell lifespan in vitro.

Chick embryo fibroblasts were maintained at confluency for up to 35 days in medium containing 0.5% or 0.75% fetal bovine serum or 2.5% or 5.0% horse serum. At weekly intervals cells were subcultured and serially propagated in medium containing 10% FBS until their replicative lifespans were completed. The results showed that the replicative lifespan of embryonic chick fibroblasts was dependent on the cumulative number of population doublings undergone by the culture and was not related to the calendar time cells were in culture. Further characterization of 0.75% FBS maintained chick cells returned to 10% FBS medium showed that cells had protein contents and incorporated 3H-thymidine into DNA at a rate that resembled that of young cells, despite an advanced chronological age.

Aging↗
PubMed1981

A comparison of the proliferative and replicative life span kinetics of cell cultures derived from monozygotic twins.

We have compared the growth rates, kinetics of cell aging, and replicative life spans of skin fibroblasts cell cultures derived from three pairs of monozygotic twins of similar ages. The results of these studies indicated no significant differences in the cell densities 7 days after inoculation or replicative life spans within each twin pair but highly significant differences among each twin pair. The kinetics by which each culture aged ([3H]thymidine-labeled nuclei) were compared within and among the twin cell cultures. Although the slopes of each regression line were not significantly different, comparisons of the elevations of each line supported the conclusion that the aging of monozygotic twin cell cultures is similar within the twin pairs but differs among the twin pairs.

Adult↗
PubMed1981

A renal inhibitor to hepatic erythropoietin [Ep] production.

Evidence is presented for the existence of a factor in renal venous blood, evoked by subtotal hepatectomy (hepx), which inhibits the production of Ep in nephrectomized (nephrx) rats exposed to hypoxia. Significant inhibitory activity is not observed in blood obtained from sites other than the renal vein. This inhibitory effect is believed to be due to the action of a specific renal inhibitory factor (RIF) which reduces the extrarenal (hepatic) Ep response to hypoxia indirectly, by decreasing the production or effectiveness of an antagonistic liver principle, the hepatic erythropoietic factor (HEF). The HEF has previously been shown to augment hepatic Ep production following hypoxia in renally-deficient animals. The RIF has no anti-Ep action and its activity is not influenced by the accumulation of metabolic wastes. A mechanism for a renal-hepatic antagonism in the Ep response to hypoxia is hypothesized.

Animals↗
PubMed1979

The kinetics of chick cell population aging in vitro.

We have examined the kinetics of chick cell population aging in vitro using the percentage of labeled nuclei, the number of colonies formed from a low density inoculum and the number of cells/colony to monitor culture age. The results from these studies showed a gradual age-associated decline in each of the parameters which was first detected early in the culture lifespan and well in advance of changes in total cell number at confluency. Our results also indicated that each of the above parameters, in addition to the calendar time cells had been in culture, could be used to estimate the percentage of lifespan completed by the culture. A comparison of the methods used to estimate the remaining culture lifespan indicated that the percentage of labeled nuclei was the most accurate in describing cell age.

Animals↗
PubMed1979

Effect of different fetal bovine serum concentrations on the replicative life span of cultured chick cells.

The effect of Eagle's minimal essential medium, containing different fetal bovine serum (FBS) concentrations, on the proliferation and replicative life span of cultured chick cells has been studied. Our results showed that the rate of chick cell proliferation and the cell density at stationary phase increased as a function of serum concentration between 5 and 30% FBS. The replicative life span of cultured chick cells was dependent on the FBS concentration between 5 and 20% in a medium volume of 0.20 ml/cm2. The maximum replicative life span of chick cells was obtained by serially propagating cells in a medium volume of 0.20 ml/cm2 containing 20 or 30% FBS, or, alternatively, in 0.53 ml/cm2 containing 10, 20 or 30% FBS. Cells grown in medium containing 5% serum had a calendar life span of 35 days, whereas cells propagated in medium containing higher serum concentrations had a calendar life span of 50 days. These results reenforce the concept that, although the kinetics of cell population aging can be affected by the culture medium composition, the aging of cells in culture is controlled by alterations within the cell.

Animals↗