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Biomedical subjects

J Slater

Publications and source records attributed to J Slater.

At least 19 recordsLinked to original sources
PubMed1992

Assessment of global and regional left ventricular performance at rest and during exercise after thrombolytic therapy for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) II Study.

Global and regional left ventricular performances were evaluated with equilibrium radionuclide angiocardiography in patients in the Thrombolysis in Myocardial Infarction (TIMI) II trial at the time of hospital discharge. Studies at rest were available in 1,162 (69%) of the invasive and 1,150 (69%) of the conservative strategy patients, and exercise studies in 1,133 (67%) of the invasive and 1,145 (69%) of the conservative patients. Repeat studies were performed at the time of 6-week follow-up. Global and regional ejection fraction at rest were both comparable in patients assigned to each of the treatment strategies. However, at the time of hospital discharge patients in the invasive strategy had normal exercise responses more frequently (29.7 vs 25.8% p = 0.01), greater peak exercise LV ejection fraction (54.8 +/- 13.8% vs 53.1 +/- 14.1%, p = 0.004), greater exercise--rest change in LV ejection fraction (3.7 +/- 6.7% vs 2.7 +/- 7.2%, p less than 0.001) and greater peak exercise infarct zone regional ejection fraction (53.2 +/- 31.1% vs 50.3 +/- 33.0%, p less than 0.001) than patients assigned to the conservative strategy. At 6-week follow-up these differences between treatment strategies were no longer evident. When data were restricted to those collected at comparable work loads, similar differences in hospital discharge exercise performance between invasive vs conservative strategy patients were observed. Thus, there is a small transient difference in exercise global and regional LV performance associated with an invasive as opposed to conservative strategy after thrombolytic therapy. These differences are noted at the time of hospital discharge but not at 6 weeks, and are unlikely to confer clinical benefit.

Chi-Square Distribution↗
PubMed1991

Comparison of cardiac catheterization and Doppler echocardiography in the decision to operate in aortic and mitral valve disease.

Clinical decisions utilizing either Doppler echocardiographic or cardiac catheterization data were compared in adult patients with isolated or combined aortic and mitral valve disease. A clinical decision to operate, not operate or remain uncertain was made by experienced cardiologists given either Doppler echocardiographic or cardiac catheterization data. A prospective evaluation was performed on 189 consecutive patients (mean age 67 years) with valvular heart disease who were being considered for surgical treatment on the basis of clinical information. All patients underwent cardiac catheterization and detailed Doppler echocardiographic examination. Three sets of two cardiologist decision makers who did not know patient identity were given clinical information in combination with either Doppler echocardiographic or cardiac catheterization data. The combination of Doppler echocardiographic and clinical data was considered inadequate for clinical decision making in 21% of patients with aortic and 5% of patients with mitral valve disease. The combination of cardiac catheterization and clinical data was considered inadequate in 2% of patients with aortic and 2% of patients with mitral valve disease. Among the remaining patients, the cardiologists using echocardiographic or angiographic data were in agreement on the decision to operate or not operate in 113 (76% overall). When the data were analyzed by specific valve lesion, decisions based on Doppler echocardiography or catheterization were in agreement in 92%, 90%, 83% and 69%, respectively, of patients with aortic regurgitation, mitral stenosis, aortic stenosis and mitral regurgitation. Differences in cardiac output determination, estimation of valvular regurgitation and information concerning coronary anatomy were the main reasons for different clinical management decisions. These results suggest that for most adult patients with aortic or mitral valve disease, alone or in combination, Doppler echocardiographic data enable the clinician to make the same decision reached with catheterization data.

Adult↗
PubMed1990

Doppler echocardiographic flow velocity measurements in the superior vena cava during the Valsalva maneuver in normal subjects.

The hemodynamic manifestations of the Valsalva maneuver are in part the result of changes in the venous return accompanying changes in intrathoracic pressure. Doppler echocardiography was performed during Valsalva maneuver in 13 normal subjects. Superior vena cava flow velocities and flow velocity integrals were measured in all 13 subjects. In the 5 subjects in whom the superior vena cava was clearly visualized throughout the maneuver, vena cava diameter was also analyzed. The superior vena cava flow velocity integral at rest was 17 +/- 2 cm. It diminished significantly, disappeared or reversed (-13 +/- 6 cm, p less than 0.001) with phase I of the maneuver. During the maintenance phase (phase II), the flow velocity integral increased significantly (31 +/- 2 cm, p = 0.05 vs baseline and phase I) and was associated with a decrease in superior vena cava lumen diameter at the time of Valsalva and continuing throughout the strain. With release of the maneuver (phase III), there was a sudden significant increase in flow velocity integral (61 +/- 2 cm, p = 0.005 vs phase II) and superior vena cava lumen diameter. Subsequently, superior vena cava flow velocity integral returned to baseline values. This study suggests that one of the ways in which the Valsalva maneuver leads to decreased venous return may be by direct external compression of the superior vena cava.

Adult↗
PubMed1990

Percutaneous double-balloon valvuloplasty of porcine bioprosthetic valves in the tricuspid position.

This is a description of the first two reported cases of double-balloon valvuloplasty in the treatment of porcine bioprosthetic valve stenosis in the tricuspid position. In both cases, the double-balloon technique resulted in a better hemodynamic improvement than single-balloon valvuloplasty and was well tolerated. Double-balloon valvuloplasty is a reasonable alternative to surgical replacement of a stenotic bioprosthesis in the tricuspid position.

Adult↗
PubMed1990

Transesophageal echocardiography to detect atrial clots in candidates for percutaneous transseptal mitral balloon valvuloplasty.

Left atrial thrombi are common in patients with mitral stenosis. When percutaneous balloon mitral valvuloplasty is performed on such patients, there is a potential risk of thrombus dislodgment and embolization. In this study conventional transthoracic echocardiography and transesophageal echocardiography were performed for percutaneous balloon mitral valvuloplasty on 19 consecutive candidates (6 men, 13 women, 23 to 81 years old). In five patients (26%), transesophageal echocardiography revealed a left atrial thrombus; in only one of these was there a suspicion of left atrial thrombus on transthoracic echocardiography. Balloon mitral valvuloplasty was canceled in four of the five patients. Three underwent mitral valve surgery that confirmed the echocardiographic findings. Transesophageal echocardiography is better than conventional transthoracic echocardiography in detecting left atrial clots in candidates for balloon mitral valvuloplasty. Because of the potential risk of embolization, transesophageal echocardiography is recommended in all candidates for balloon mitral valvuloplasty.

Catheterization↗
PubMed1990

Discrete atherosclerotic coronary artery aneurysms: a study of 20 patients.

The incidence, angiographic features and natural history of discrete atherosclerotic coronary aneurysms were evaluated in 20 patients with 22 aneurysms (0.2% of 8,422 patients referred for coronary angiography). Fifteen aneurysms (68%) were in the left anterior descending, four (18%) in the circumflex, two (9%) in the right and one (5%) in the left main coronary artery. Aneurysm diameter ranged from 4 to 35 mm (mean 8); 95% of aneurysms were adjacent to a severe obstruction. Seventy-five percent of patients had severe triple vessel disease that included severe left main disease in 15%. Total obstruction of one or two arteries was present in 75%. In patients with wall motion abnormalities, 78% of the abnormalities were in the distribution of the aneurysm. Follow-up (range 1 to 90 months [mean 30]) was obtained in all 20 patients. There were two cardiac and two noncardiac deaths; 12 patients had coronary bypass surgery and of 16 survivors, 13 were angina-free. In conclusion, discrete coronary aneurysms are much less common than diffuse ectasia. Unlike ectasia, they are never found in arteries without severe stenosis, and are most common in the left anterior descending coronary artery. Associated coronary artery disease is more severe in patients with discrete aneurysms than in those with diffuse ectasia. Discrete coronary aneurysms do not appear to rupture, and their resection is not warranted.

Aged↗
PubMed1990

Effecting personal effectiveness: assertiveness training for nurses.

This paper describes a client-centred approach to assertiveness training with nurses. The approach recognizes and utilizes the skills and resources within a group, through a process of enabling rather than teaching. The group's own knowledge and experiences are shown to be at least as valid as other academic and research texts which are referred to. In personal development terms they are more valid. Technique-based courses are thought to have less impact than this approach, clearly rooted in self-awareness and development. After looking at the history of assertiveness training, and ways of defining it, the paper goes on to describe the process and content of a programme which is group led. Space is also given to considering why it may be particularly difficult for nurses to act assertively, due to tradition and stereotypes.

Assertiveness↗
PubMed1989

Fallopian tube carcinoma: a clinicopathological study of 17 cases.

From 1969 through 1986, 17 patients with primary adenocarcinoma of the fallopian tube were treated at the Loma Linda University Medical Center. Stages I, II, and III of the disease were present in 6, 5, and 6 patients, respectively. The mean age of the patients was 59.9 years. Vaginal bleeding or discharge (57%), followed by abdominal pain or discomfort (29%), was the most common symptom in our patients. A palpable pelvic mass was detected in two-thirds of the patients. One case of carcinosarcoma, one case of mixed mesodermal tumor, and one case of endometrioid carcinoma are included. No patient in this series had a correct preoperative diagnosis. Therapy consisted of surgical resection, usually followed by various combinations of adjuvant radiation therapy and/or chemotherapy. The overall 5-year survival rate was 31%. Five patients (29%) are alive without evidence of disease. This study supports the need for collaboration among large centers to define the optimal adjuvant therapy of this disease. In the absence of the desired treatment protocols, such lesions should be approached in a manner similar to that used for ovarian cancers.

Adenocarcinoma↗
PubMed1989

Regional hyperthermia for advanced tumors: a clinical study of 353 patients.

A Phase I study using deep regional hyperthermia (HT) with an annular phased array was conducted in 14 U.S. medical centers from 1980 through 1986. There were 353 patients whose average age was 57 years. All patients had advanced recurrent or persistent tumors. Prior frequently complex, multimodality anti-cancer therapy was received by 71% of the patients. Gastrointestinal adenocarcinoma was present in 146 (41%) patients, genitourinary tumors in 86 (24%), soft tissue sarcomas in 46 (13%), malignant melanoma in 21 (6%) and 15% had other tumors. The sites treated included: pelvis 55%, abdomen 21%, liver 14%, thorax 6%, and other sites 3%. All patients received deep regional HT with an average frequency of 55 MHz. A total of 1412 HT treatments was administered to these 353 patients with an aim to increase the temperature in the volume of interest to greater than 42 degrees C for greater than or equal to 30 minutes. Thermal dose (TD in equivalent minutes at 42.5 degrees C) was less than 50 in 104 (29%), greater than or equal to 50 less than 100 in 30 (11%), greater than or equal to 100 in 26 (7%), and greater than 200 in 34 (10%). The remaining 150 (42%) patients had TD = 0. In addition to HT, 260 (74%) received radiotherapy (RT). RT was given at 180 or 200 cGy daily with an average total dose of 33.4 Gy. A total of 42 (12%) patients were given chemotherapy (CT) with HT, and 15 (4%) CT + HT + RT/HT alone was given to 47 (13%) patients. Complete response (CR) was obtained in 35 (10%) and partial response (PR) in 59 (17%) patients. CR was 12% in patients who received RT, vs 2% in those who did not receive it, p = 0.003. Radiation dose was an important factor influencing response, p less than 0.001. Thermal dose was not an important parameter influencing tumor response. A duration of CR ranged from 4 to 73 weeks with an average duration of 31 weeks and the median duration of 28 weeks. The overall 2-year survival was 13% with the median survival of 42 weeks. Patients with CR and PR had a 2 year survival of 41%, and a median survival of 71 weeks. This compared with 8% 2-year survival and 24 weeks median survival in patients who did not have CR or PR, p less than 0.001. Of the patients presenting with significant pain, 62% had complete or partial pain relief.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Genetic conditions among Canadian Mennonites: evidence for a founder effect among the old colony (Chortitza) Mennonites.

Distinctive disease patterns exist among Canadian Old Colony (Chortitza) Mennonites. This religious and genetic isolate is of 16th century Dutch/German ancestry. The group originated in the Netherlands, then settled in the Vistula delta area of western Prussia for 200 years. A small number of founding families later migrated to Chortitza, the "Old Colony", in the Ukraine in the late 18th/early 19th century, where they remained a distinct genetic isolate. This group has come to Canada over the past 100 years. The more conservative Canadian Mennonites of Chortitza descent practice strict endogamy, have a large family size and live predominantly in rural public health subdistricts in the four western provinces, and in southern Ontario. The world's largest reported familial aggregations of insulin-dependent diabetes mellitus, of autoimmune diseases and of Tourette syndrome were initially ascertained in a small northern Alberta public health subdistrict. Clusterings of malformations, inborn errors of metabolism, and other conditions were also found in the subdistrict, and in group descendents living in other provinces. A founder effect, or genetic drift, accounts for the familial aggregations of autosomal recessive and dominant conditions, some diseases of multifactorial determination, and other inherited conditions in Canadian kinships descending from this ancestral group. The medical literature on genetic conditions among Canadian Mennonites is reviewed and re-evaluated in the light of this information. There is biochemical, serologic, and molecular biologic evidence in favour of genetic homogeneity amongst patients with certain inherited conditions in this special population group. This genetic isolate offers potential for the study of the genetic epidemiology and molecular biology of inherited diseases. A computerized genealogic data base on about 1400 group members, as well as a cryopreserved lymphocyte/DNA bank on over 100 individuals with genetic conditions has been established in this special population group.

Alberta↗
PubMed1988

Conservative treatment of uveal melanoma: probability of eye retention after proton treatment.

Enucleation was performed after proton treatment in 57 of 1006 (5.7%) uveal melanoma patients treated with proton beam therapy at the Harvard Cyclotron Laboratory between July 1975 and December 31, 1986. Only 2% of 99 patients with small tumors and 4% of 566 patients with intermediate size tumors underwent enucleation after treatment; 10% of 341 patients with large tumors lost the treated eye. No eyes were removed after 52 months, with 89% of enucleations performed during the first 36 months after treatment. Eye retention rates at 60 months were 89.1 +/- 3.0% for the entire group, and 97 +/- 3.7%, 92.7 +/- 3.1%, and 78.3 +/- 7.0% in patients with small, intermediate, and large tumors, respectively. Significantly greater enucleation rates were observed in patients with large tumors than in those with intermediate tumors (p = less than .0001), in patients with tumor height greater than 8 mm relative to those with tumors less than or equal to 8 mm, p = (less than .0001), with tumor diameter greater than 16 mm compared to less than or equal to 16 mm, (p = less than .0001), and with tumor involvement of the ciliary body compared to involvement of the choroid only (p = less than .0001). Possible strategies to decrease the likelihood of enucleation in patients at apparently increased risk of losing the eye after conservative therapy, that is, those with large tumors involving the ciliary body, might include a lower total dose, a more protracted treatment course, or a lower radiation dose and adjuvant treatment with chemotherapy and/or immunotherapy, with hyperthermia, or with other radiation sensitizers.

Actuarial Analysis↗
PubMed1988

Passive sensitization and antigen challenge increase vascular permeability in rat airways.

Activation of mast cells in all organs in which this phenomenon has been studied leads to increased vascular permeability. Mucosal edema is thought to be an important component of the airflow obstruction of asthma. In order to develop a model to study IgE-mediated vascular permeability in lung, rats were passively sensitized with a murine monoclonal IgE-anti-dinitrophenyl (DNP). Forty-eight hours later, the animals were challenged intravenously with mouse serum albumin conjugated to DNP (1 to 25 micrograms) and received 125I-labeled bovine albumin at the same time to permit assessment of leakage of vascular proteins into the lungs. The animals became cyanotic, but they did not die. Control animals were challenged with mouse serum albumin alone and experienced no systemic reactions. The trachea, the hilum, and peripheral lung were removed and the radioactivity determined. Compared to control animals, vascular permeability was increased most impressively in the trachea and to a lesser extent in the hilum. No increased vascular permeability was found in the peripheral lung. In dose-response experiments (1 to 25 micrograms MSA-DNP injected), the peak effect in the trachea occurred at 25 micrograms MSA-DNP (+450 +/- 119% above control values, p less than or equal to 0.05), while the response in the bronchus was less dose dependent; maximal increase above control was at 12.5 micrograms DNP-MSA (+50 +/- 8%, p less than or equal to 0.05). The increased plasma exudation in the trachea and bronchi peaked within 5 min of antigen challenge and remained significantly increased for at least 2 h. After 8 h, no increased radioactivity could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

IgE-immunotoxins. II. IgE-ricin A-chain.

In order to develop a reagent capable of killing cells with high-affinity IgE Fc receptors, such as mast cells and basophils, ricin A-chain (the toxic portion of ricin) was conjugated to rat IgE myeloma protein, IR 162, via derivatization of the IgE by n-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) thus creating an IgE-immunotoxin. Monensin (10(-7)-10(-8)M), a carboxylic ionophore, facilitated IgE-ricin A-chain (3 X 10(-7)M) toxicity in a dose-related fashion ith significant reductions in [3H]leucine incorporation compared to cells exposed only to monensin. This enhanced toxicity could be inhibited by the addition of both anti-ricin A-chain or anti-IgE, suggesting that different routes of intracellular processing may play a role in determining the toxicity of the IgE-ricin A-chain conjugate. Ricin B-chain (5 X 10(-7) and 5 X 10(-8)M) added to free ricin A-chain (10(-6)-10(-8)M) reproducibly facilitated toxicity, and this toxicity could be inhibited (30-90%) by lactose (50 mM). Ricin B-chain also facilitated IgE-ricin A-chain (2.75 X 10(-8)M) toxicity; however, this toxicity was not affected by lactose. The data suggest that ricin B-chain potentiates the cytosolic access of internalized IgE-immunotoxin and that the binding and internalization of the toxin was mediated via the IgE Fc receptor. A second type of IgE-ricin A-chain conjugate was synthesized whereby both IgE and ricin A-chain were derivatized with SPDP. RBL cells were killed in a dose-dependent manner by this IgE-ricin A-chain conjugate (2.5 X 10(-6)-2.5 X 10(-9)M) without requiring the addition of monensin or ricin B-chain. These data indicate that the intracellular route and processing of internalized immunotoxin is critical to eliciting toxicity.

Animals↗
PubMed1986

Long-term follow-up after mitral valve reconstruction: incidence of postoperative left ventricular outflow obstruction.

Reconstructive surgery of the mitral valve has been an alternative to mitral valve replacement in patients with mitral regurgitation. Previously, we reported on postoperative left ventricular outflow tract obstruction associated with systolic anterior motion of the anterior mitral leaflet. The current study was designed to evaluate the incidence of this complication and the long-term results of mitral valve reconstructive surgery. Sixty-five patients, aged 19 to 78 years, had mitral valve reconstructive surgery. Two patients died perioperatively, and three died late after surgery. The 60 surviving patients were studied by M mode, two-dimensional, and Doppler echocardiography 1 to 55 months postoperatively (mean 21). Fifty patients had no evidence of postoperative mitral regurgitation, two patients had moderate mitral regurgitation, three patients had mild mitral regurgitation, and five patients had trace mitral regurgitation. No significant mitral stenosis was detected in any patient postoperatively. After surgery, the diameter of the left ventricular outflow tract was significantly smaller than that before surgery. The echocardiograms of six patients showed abnormal systolic anterior motion of the anterior mitral leaflet that was not observed preoperatively. Doppler echocardiography demonstrated pressure gradients across the left ventricular outflow tract between 10 and 64 mm Hg. Inhalation of amyl nitrite increased these gradients. An additional patient who had systolic anterior motion but no gradient developed a 36 mm Hg gradient after inhalation of amyl nitrite. The remaining patients had no gradient induced by amyl nitrite. Abnormal systolic anterior motion of the anterior mitral leaflet may be surgically induced by changes in left ventricular geometry and the size of the left ventricular outflow tract during systole.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗