Effect of coronary reocclusion after initial reperfusion on ventricular function and infarct size.

Reocclusion of a coronary artery after thrombolytic therapy occurs in approximately 12% to 33% of patients; however, there are few experimental data concerning reocclusion. Accordingly, to compare the effects of reocclusion versus sustained occlusion on the myocardium, a canine model (n = 12) of 2 h of left circumflex artery occlusion, 1 h of reperfusion and 1 h of reocclusion was studied. In a control group (n = 11), 3 h of circumflex artery occlusion was followed by 1 h of reperfusion. As a result, both groups had the same total duration of ischemia (3 h) and reperfusion (1 h). Hemodynamic measurements, radioactive microsphere injections and two-dimensional echocardiography were performed at baseline, occlusion and reperfusion for both groups and at the end of reocclusion for the experimental group. In vivo risk area was determined with Evans blue dye and infarct size with triphenyltetrazolium staining methods. Similar decreases in myocardial blood flow after coronary occlusion and similar reperfusion blood flows occurred in both groups. Despite intervening reperfusion in the reocclusion group, no significant difference was found in the infarct size/risk area ratio between the reocclusion and control groups (54.5 +/- 6.9% vs. 48.4 +/- 5.1%, respectively, p = NS). Two-dimensional echocardiography demonstrated a similar degree and extent (159 +/- 9 degrees vs. 153 +/- 12 degrees, p = NS) of left ventricular dysfunction with both the occlusion and reocclusion. In addition, there were no significant differences in global or regional left ventricular function between the two groups. However, reocclusion after reperfusion did produce a further deterioration in ischemic zone wall thickening (9.5 +/- 2.0% to 0.7 +/- 1.8%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

An investigation of the efficacy of super-oxidised (Optident/Sterilox) water for the disinfection of dental unit water lines.

AIMS: To determine the efficacy of super-oxidised water (Optident/Sterilox) in the decontamination of dental unit water lines. METHODS: Dental units (10) were first purged with concentrated super-oxidised water. After purging, a 5% (v/v) super-oxidised water was used as a maintenance dose. Samples for microbiology were taken after 0,1,2,3,4,5,6,7 d, and each week for a further 13 weeks. RESULTS: After purging, 5% (v/v) super-oxidised water was successful in reducing the microbial counts to zero, although in three of the units some bacteria were intermittently isolated in the first week of treatment. CONCLUSIONS: Super-oxidised water was successful in the removal of bacteria from dental unit water supplies. Complete removal required the treatment with a purge phase of concentrated disinfectant and a maintenance phase of at least two weeks.

Intravascular ultrasound imaging of vascular responsiveness in isolated perfused canine arteries.

We investigated the feasibility of using intravascular ultrasound imaging to analyze vascular physiology in various arterial beds. Canine superficial femoral, external iliac, and common carotid arteries were harvested and suspended and perfused in a bath of oxygenated, heated, physiologic salt solution. A 6-Fr, 20-MHz ultrasound imaging catheter was inserted into the lumen of the arteries and serial images were acquired after bolus injections of either serotonin or normal saline into the extravascular bathing medium. Serotonin resulted in a significant time- and dose-dependent decrease in cross-sectional area in muscular femoral arteries (P less than .001): -5.2% with 10(-8) M serotonin, -15% with 10(-7) M, and -28% with 10(-6) M. Histologically transitional iliac arteries demonstrated less marked changes, while elastic carotid arteries demonstrated no significant changes. Our results indicate that intravascular ultrasound may be used to quantify and differentiate responses to vasoconstrictive agents in different vascular beds.

Microbial contamination of donor eyes. A retrospective study.

The culture results of 4,167 donor eyes received over a two-year period are evaluated. Irrigation of the cornea and conjunctiva with 20 mL of sterile saline prior to enucleation decreased the incidence of bacterial contamination to 12.4%. The major contaminant is Staphylococcus epidermidis (66.4%). The incidence of endophthalmitis in the 1,880 corneal transplants performed during this time was 0.1%. The significance of irrigation and antibiotic use in processing donor corneas is discussed

Adjustable model of chronic left ventricular dysfunction.

BACKGROUND: As an adjunct to the development of skeletal muscle-powered left ventricular assist devices, an adjustable model of chronic left ventricular failure was developed. METHODS: Implantation of a left ventricular balloon to induce heart failure was accomplished via left thoracotomy. Upon recovery, left ventricular failure was simulated by manipulation of left ventricular balloon volume to chronically raise left atrial pressure. RESULTS: Left atrial pressure increased from a baseline of 9.3 +/- 0.7 mm Hg to 18.5 +/- 1.2 mm Hg, 20.2 +/- 1.8 mm Hg, and 26.0 +/- 1.2 mm Hg by the 2nd, 6th, and 10th postoperative week, respectively. Cardiac index declined from a baseline of 4.4 +/- 0.3 L x min(-1) x m(-2), reaching stability by the 8th postoperative week at 3.0 +/- 0.4 L x min(-1) x m(-2). Stroke volume index declined from 1.12 +/- 0.1 mL x kg(-1) x beat(-1) to 0.60 +/- 0.1 mL x kg(-1) x beat(-1) by the 10th postoperative week. Mean survival was 75 +/- 7 days. Causes of death included left ventricular failure, thromboembolism, and euthanasia. CONCLUSIONS: This method of simulating chronic left ventricular dysfunction proved to be stable and adjustable and has been useful in the development of ventricular assist systems.

Delta opioid receptors and low temperature myocardial protection.

BACKGROUND: Cardiac surgery continues to be limited by an inability to achieve complete myocardial protection. This may result from the use of hypothermic cardioplegia. Interestingly, the subcellular changes of animal hibernation parallel the altered biology of induced hypothermic myocardial ischemia, but are well tolerated by hibernated mammalian myocardium. Evidence indicates this protection is mediated by activation of the delta opioid receptor, which elicits profound metabolic effects at the whole animal, organ, and cell level. In this study, we sought to determine if pentazocine, with agonist activity at the delta opioid receptor, could improve myocardial recovery following global ischemia over a wide range of temperatures. METHODS: Isolated rabbit hearts received either standard cardioplegia or were pretreated with racemic, d or 1 isomer pentazocine. Hearts were then subjected to 2 hours at 34 degrees C, or 3.5 hours at 20 degrees C, or 4 hours at 10 degrees C of cardioplegic ischemia and reperfused. Functional recovery was compared to controls. RESULTS: Isovolumic developed pressure, coronary flow, oxygen consumption, and ultrastructural preservation were enhanced with pentazocine delta opioid mediated protection, which appears to be additive to standard cardioplegia, even at low temperatures. CONCLUSIONS: Teleologically, delta opioid protection parallels animal hibernation, which occurs from 34 degrees down to 0 degrees C. The use of delta opioid receptor agonists may have important clinical implications for cardiac surgery and deserves further study.

Long-term functional outcome of repair of large and massive chronic tears of the rotator cuff.

BACKGROUND: There have been conflicting reports regarding the effect of the size of a tear of the rotator cuff on the ultimate functional outcome after repair of the rotator cuff. While some authors have reported that the size of the tear does not adversely affect the overall result of repair, others have reported that the outcome is less predictable after repair of a large tear than after repair of a small tear. The purpose of the present study was to examine the long-term functional outcome and the recovery of strength in thirty consecutive patients who had had repair of a large or massive tear of the rotator cuff. METHODS: Thirty consecutive patients who had operative repair of a large or massive chronic tear of the rotator cuff had a comprehensive isokinetic assessment of the strength of the shoulder preoperatively, twelve months postoperatively, and a mean of sixty-five months (range, forty-six to ninety-three months) postoperatively. The functional outcome was assessed with the University of California at Los Angeles shoulder score. RESULTS: All patients reported that they were satisfied with the result and had increased strength compared with preoperatively. There was a significant decrease in pain (p < 0.01) and significant improvements in function (p < 0.01) and the range of motion (p < 0.01). The mean University of California at Los Angeles shoulder score increased significantly from 12.3 points preoperatively to 31.0 points at the most recent follow-up examination (p < 0.01). The mean peak torque in flexion, abduction, and external rotation increased significantly to 80 percent (p < 0.01), 73 percent (p < 0.01), and 91 percent (p < 0.01), respectively, of that of the uninvolved shoulder by the time of the most recent follow-up examination. CONCLUSIONS: Repair of a large or massive tear of the rotator cuff can have a satisfactory long-term outcome. The results of the present study suggest that more than one year is needed for complete restoration of strength. The strength of the affected shoulders still did not equal that of the unaffected, contralateral shoulders by the time of the long-term follow-up.

Functional outcome after minimally displaced fractures of the proximal part of the humerus.

One hundred and four patients who had a minimally displaced fracture of the proximal part of the humerus (a so-called one-part fracture) were managed with a standardized therapy regimen and followed for more than one year. The clinical outcome was assessed on the basis of pain, function, and the range of motion of the shoulder. The duration of follow-up averaged forty-one months (range, twelve to 117 months). All fractures united without additional displacement. Eighty patients (77 per cent) had a good or excellent result, fourteen (13 per cent) had a fair result, and ten (10 per cent) had a poor result. Ninety four patients (90 per cent) had either no or mild pain in the shoulder, eight (8 per cent) had moderate pain, and two (2 per cent) had severe pain. Functional recovery averaged 94 per cent; forty-eight patients (46 per cent) had 100 per cent functional recovery. At the time of the most recent follow-up, forward elevation of the injured shoulder averaged 89 per cent; external rotation, 87 per cent; and internal rotation, 88 per cent that of the uninjured shoulder. The percentage of good and excellent results was significantly greater (p < 0.01) and external rotation was significantly better (p < 0.01) at the time of the latest follow-up for the patients who had started supervised physical therapy less than fourteen days after the injury than for the patients who had started such therapy at fourteen days or later.

Human immunodeficiency virus and immigration status in the United States.

The number of HIV-infected immigrants is increasing in cities across the United States. A case study explores the complexities of the immigration process as it relates to HIV infection; implications for nursing practice are discussed. By understanding the immigration process, nurses are able to identify and refer illegal residents who are HIV infected to appropriate social-service agencies, thereby providing more comprehensive care to patients and their families.

Open surgical treatment of anterior glenohumeral instability: an historical perspective and review of the literature. Part I.

Anterior glenohumeral instability is an undesirable result of trauma to the shoulder. Several surgical treatments for this condition have been developed, beginning in the early years of the twentieth century. Although these procedures were usually popular at their inception, many of them have fallen out of favor as more information has been acquired concerning the long-term results and complications of their use. Often successful in preventing recurrent instability, these earlier procedures also often led to a loss of external rotation, and consequently, function. Newer procedures that aim to prevent recurrent instability while maintaining full range of motion and function have been devised. Part I of this paper presents a brief history of the treatment of glenohumeral instability and a review of the literature, including the Bankart and du Toit procedures. Part II, which will be published in the December 1998 issue, includes the Putti-Platt, Magnuson-Stack, Bristow, and newer procedures.

Open surgical treatment of anterior glenohumeral instability: an historical perspective and review of the literature. Part II.

Anterior glenohumeral instability is an undesirable result of trauma to the shoulder. Several surgical treatments for this condition have been developed, beginning in the early years of the twentieth century. Although many of these procedures were popular at their inception, many of them have fallen out of favor as more information has been acquired concerning the long-term results and complications of their use. While often successful in preventing recurrent instability, these earlier procedures also often led to a loss of external rotation, and consequently, function. Newer procedures have been devised that aim to prevent recurrent instability while maintaining full range of motion and function. Part I of this paper, published in the November issue, presented a brief history of the treatment of glenohumeral instability and a review of the literature, including the Bankart and du Toit procedures. Part II includes the Putti-Platt, the Magnuson-Stack, the Bristow, and capsular shift procedures.

Hemiarthroplasty for cuff tear arthropathy.

A retrospective review was conducted on 15 cases of shoulder hemiarthroplasty performed for cuff tear arthropathy. All cases had advanced glenohumeral arthritis with complete supraspinatus and infraspinatus rupture and substantial involvement of the teres minor and subscapularis. The mean patient age was 73 years; the mean follow-up was 28.2 months. Range of motion, functional ability, pain relief, and overall patient satisfaction were assessed preoperatively and postoperatively. The average active forward elevation increased from 69 degrees to 86 degrees, and the average active external rotation increased from 15 degrees to 29 degrees. Thirteen patients had an increase in their ability to perform activities of daily living, 1 patient was unchanged, and 1 patient had a decrease in ability to perform activities of daily living. Pain relief was significantly improved in all but 1 patient. Eleven patients (13 of 15 shoulders, 87%) expressed an overall satisfaction with their surgery. Patients were assessed preoperatively and postoperatively through use of the UCLA Rating Scale; the average increase was 11 to 22 points. In addition, isokinetic strength testing was performed preoperatively and postoperatively on 6 of the 15 involved shoulders. An increase in peak torque in forward elevation, abduction, and external rotation was noted postoperatively. The findings of this study indicate that favorable clinical results can be obtained after hemiarthroplasty of the shoulder with associated massive rotator cuff deficiency.

Effects of age, testing speed, and arm dominance on isokinetic strength of the elbow.

The strength of active flexion/extension and supination/pronation was measured isokinetically in 60 right-hand-dominant nonathletic men. They were equally divided into a younger group (20 to 30 years) and an older group (50 to 60 years) with moderate occupational and spare-time activity levels. Peak torque, work, power, and the angle of peak torque production were measured bilaterally at a slow (90 degrees/sec) and a fast (180 degrees/sec) speed of movement. Although highly significant differences were found between the young and older groups in flexion and extension, no age-related differences were found in supination and pronation. The dominant side had significantly higher levels of peak torque, work, and power in flexion; however, no significant differences were detected in peak torque for extension, supination, and pronation. Isokinetic peak torque and work were greater at the slower speed as opposed to power, which was significantly greater at the faster speed with the exception of pronation movement. With regard to the angle where peak torque was achieved, significant differences were detected between groups, which suggests that age appears to affect where in the range of motion peak torque is produced.

Strength after surgical repair of the rotator cuff.

Forty-two consecutive patients (20 men and 22 women, age range 39 to 78 years) with full-thickness rotator cuff tears underwent a comprehensive isokinetic strength assessment before and at 3-month intervals for 1 year after surgery. All patients underwent acromioplasty and rotator cuff repair and were treated with a standardized postoperative rehabilitation program. Isokinetic strength testing was performed in flexion/extension, abduction/adduction, and external/internal rotation at 60 degrees/sec. The unaffected contralateral shoulder was tested for comparison. Clinical outcomes were assessed with the University of California Los Angeles Shoulder Rating Scale (maximum = 35 points). The average University of California Los Angeles score was 31.2 by 1 year after operation. Patients with small and medium tears had an average rating of 33.5, whereas those with large and massive tears had an average score of 28.3. Strength increased gradually during the first postoperative year. The preoperative mean peak torque was 54%, 45%, and 64% of the uninvolved shoulder in flexion, abduction, and external rotation, respectively; after operation it increased to 78%, 80%, and 79% by 6 months and 84%, 90%, and 91% by 12 months. The greatest improvement in strength consistently occurred during the first 6 months after surgery. Patients also showed marked increases in both work and power. By 12 months after operation mean work had increased to 70% in flexion and abduction and 90% in external rotation of the uninvolved shoulder. Similarly, mean power had increased to 68%, 79%, and 90% of the uninvolved shoulder in flexion, abduction, and external rotation, respectively, by 12 months after operation. Recovery of strength correlated primarily with the size of the tear: for small and medium tears recovery of strength was almost complete during the first year, and for large and massive tears it was much slower and less consistent. By using isokinetic strength evaluation we found that recovery of strength after rotator cuff repair requires at least 1 year of rehabilitation.

The effect of age, speed, and arm dominance on shoulder function in untrained men.

Bilateral shoulder motor output measurements were obtained in 40 subjects with a Biodex dynamometer. The subjects included two groups, a younger group (20 to 30 years) and an older group (50 to 60 years). They were engaged in low to moderate levels of occupational and spare-time physical activity. Each subject performed three maximum effort shoulder movements in flexion/extension, abduction/adduction, and internal/external rotation at 60 degrees/sec and 120 degrees/sec. Side tested, axis, and speed were randomly selected. The findings indicate that a significant decline occurred in peak torque, work, and power for all axes of movement at both speeds when the older group was compared with the younger group. A decline in peak torque and work and a corresponding increase in power resulting from an increase in speed occurred in both age groups. The effect of age was the same at 60 degrees/sec and at 120 degrees/sec. Overall, no difference in dominant and nondominant motor function was seen in either the younger or older untrained men.

Functional outcome after humeral head replacement for acute three- and four-part proximal humeral fractures.

Twenty-six hemiarthroplasties were performed for acute three- and four-part proximal humerus fractures between March 1986 and December 1991. Postoperative pain, active range of motion, and function were evaluated in 22 patients at a mean follow-up period of 30 months (range 12 to 66 months) with the American Shoulder and Elbow Surgeons evaluation form. Seventy-three percent of patients reported only slight or no pain. Active forward elevation averaged 107 degrees, external rotation averaged 31 degrees, and the average internal rotation was to the second lumbar vertebra. Strength and stability were rarely problematic. Seventy-three percent of patients reported difficulty with at least three of 15 functional tasks tested. Lifting, carrying a weight, and using the hand at or above shoulder level were the most common limitations. This study indicates that hemiarthroplasty for acute three- and four-part fractures generally can be expected to result in painfree shoulders. However, recovery of function and range of motion are much less predictable.

Normal shoulder proprioception and the effect of lidocaine injection.

The purpose of this study was to investigate the effect of age, dominance, joint position, and lidocaine injection on proprioception of the normal shoulder. Position sense and the detection of passive shoulder motion were investigated in 40 young (20 to 30 years) and old (50 to 70 years) subjects. An additional 20 young subjects were tested before and after a glenohumeral (n = 10) or a subacromial (n = 10) lidocaine injection was performed. A significant decline occurred in proprioception between the young and old age groups. No difference was observed between dominant and nondominant sides. Position sense was consistently less accurate in the maximum range of motion tested when compared with the lesser ranges tested for flexion and abduction. No differences were identified in the ability to detect motion in flexion, abduction, and external rotation in the younger group, whereas in the older group a difference was observed in flexion. No learning effect was detected for any test trial. No significant changes occurred in proprioceptive ability after either glenohumeral or subacromial lidocaine injection was performed.

RSR13, a synthetic allosteric modifier of hemoglobin, improves myocardial recovery following hypothermic cardiopulmonary bypass.

BACKGROUND: During hypothermic blood cardioplegia, oxygen delivery to myocytes is minimal with ineffective anaerobic metabolism predominating. RSR13, 2-[4-[[(3,5-dimethylanilino) carbonyl]methyl]phenoxy]-2-methylpropionic acid, a synthetic allosteric modifier of hemoglobin (Hb), increases release of oxygen from Hb, increasing oxygen availability to hypoxic tissues, and reverses the hypothermia-dependent increase in Hb oxygen affinity. We studied recovery of myocardial mechanical and metabolic function and examined myocardial morphology after cardioplegia, comparing RSR13 (1.75 mmol/L)-supplemented blood (RSR13-BC) to standard blood cardioplegia (BC). METHODS AND RESULTS: Twelve dogs underwent 15 minutes of 37 degrees C global ischemia on cardiopulmonary bypass, followed by 75 minutes of hypothermic cardioplegia (13 degrees C) with either BC (n=6) or RSR13-BC (n=6). There were no differences in baseline function between groups. Cardiac function was assessed after 30 minutes of 37 degrees C reperfusion (BC versus RSR13-BC, respectively) by measuring: % return to normal sinus rhythm (0/100%), % of baseline+dP/dt (33.7+/-1.7/76.3+/-1.9), % of baseline-dP/dt (26.6+/-2.0/81.1+/-1.6), stroke volume (3.5+/-0.5/7.1+/-0.9 mL), cardiac output (340+/-20/880+/-40.3 mL/min), and LVEDP (11.3+/-2.2/0. 3+/-2.9 mm Hg). Postischemic oxidative and metabolic parameters including myocardial lactate, pyruvate, ATP content, and percent water content also were determined. Histological analysis demonstrated preservation of endothelial and myocyte morphology in hearts receiving RSR13-BC compared with BC. CONCLUSIONS: These results indicate that in the setting of hypothermic cardiopulmonary bypass, RSR13 improves recovery of myocardial mechanical and metabolic function compared with standard hypothermic BC. Findings from this study suggest that RSR13-BC, by decreasing hemoglobin oxygen affinity, improves oxidative metabolism and preserves cellular morphology, resulting in significantly improved contractile recovery on reperfusion.