Early angiotensin converting enzyme inhibitor therapy enhances the benefits of late coronary artery reperfusion on infarct expansion.

BACKGROUND: Individually, both late reperfusion and early angiotensin converting enzyme (ACE) inhibitor treatment prevent infarct expansion after acute myocardial infarction. OBJECTIVE: To examine the effect and mechanism of early post-myocardial infarction ACE inhibitor treatment, when used in combination with late coronary artery reperfusion, on infarct expansion. METHODS: Sprague-Dawley rats underwent 8 h of coronary occlusion followed by permanent reperfusion. The treatment group received enalapril, started 1 h after coronary occlusion and continued for 13 days. A control group received placebo. Two weeks after acute myocardial infarction, hemodynamic, morphometric and histologic analyses were performed. RESULTS: Hemodynamic parameters were similar in both groups (P = NS). Infarct size was similar in the ACE inhibitor and placebo treatment groups (44 +/- 4% compared with 39 +/- 4%, P = NS). Septal thickness was also similar in the two groups (2.8 +/- 0.3 mm compared with 2.7 +/- 0.3 mm, P = NS). The ACE inhibitor-treated group had thicker infarcts than those in the placebo-treated group (0.93 +/- 0.07 mm compared with 0.76 +/- 0.04 mm, P < 0.05) and these infarcts were less expanded (expansion index 1.17 +/- 0.12 compared with 1.57 +/- 0.12, P < 0.05). ACE inhibitor treatment was associated with hypertrophy of viable myocytes within the scar compared with placebo treatment (cell diameter 11.1 +/- 0.5 microns compared with 8.9 +/- 0.4 microns, P < 0.01). CONCLUSIONS: Early post-myocardial infarction ACE inhibitor treatment enhances the benefits of late coronary reperfusion on infarct expansion. The benefits may be related to hypertrophy of still-viable myocytes within the infarcted zone.

Scombroid poisoning.

Scombroid poisoning is described in the literature as a toxic poisoning caused by ingestion of certain dark meat fish undergoing bacterial decomposition. Poisoning results from the ingestion of a heat-stable toxin. We describe the case of a man who presented to the emergency department several hours after eating tuna steak with evidence of scombroid poisoning that was associated with loss of vision and atrial tachycardia with block. All signs and symptoms resolved after treatment for scombroid poisoning.

Relation of systemic and local muscle exercise capacity to skeletal muscle characteristics in men with congestive heart failure.

OBJECTIVES: The present study was undertaken to further characterize changes in skeletal muscle morphology and histochemistry in congestive heart failure and to determine the relation of these changes to abnormalities of systemic and local muscle exercise capacity. BACKGROUND: Abnormalities of skeletal muscle appear to play a role in the limitation of exercise capacity in congestive heart failure, but information on the changes in muscle morphology and biochemistry and their relation to alterations in muscle function is limited. METHODS: Eighteen men with predominantly mild to moderate congestive heart failure (mean +/- SEM New York Heart Association functional class 2.6 +/- 0.2, ejection fraction 24 +/- 2%) and eight age- and gender-matched sedentary control subjects underwent measurements of peak systemic oxygen consumption (VO2) during cycle ergometry, resistance to fatigue of the quadriceps femoris muscle group and biopsy of the vastus lateralis muscle. RESULTS: Peak VO2 and resistance to fatigue were lower in the patients with heart failure than in control subjects (15.7 +/- 1.2 vs. 25.1 +/- 1.5 ml/min-kg and 63 +/- 2% vs. 85 +/- 3%, respectively, both p < 0.001). Patients had a lower proportion of slow twitch, type I fibers than did control subjects (36 +/- 3% vs. 46 +/- 5%, p = 0.048) and a higher proportion of fast twitch, type IIab fibers (18 +/- 3% vs. 7 +/- 2%, p = 0.004). Fiber cross-sectional area was smaller, and single-fiber succinate dehydrogenase activity, a mitochondrial oxidative marker, was lower in patients (both p < or = 0.034). Likewise, the ratio of average fast twitch to slow twitch fiber cross-sectional area was lower in patients (0.780 +/- 0.06 vs. 1.05 +/- 0.08, p = 0.019). Peak VO2 was strongly related to integrated succinate dehydrogenase activity in patients (r = 0.896, p = 0.001). Peak VO2, resistance to fatigue and strength also correlated significantly with several measures of fiber size, especially of fast twitch fibers, in patients. None of the skeletal muscle characteristics examined correlated with exercise capacity in control subjects. CONCLUSIONS: These results indicate that congestive heart failure is associated with changes in the characteristics of skeletal muscle and local as well as systemic exercise performance. There are fewer slow twitch fibers, smaller fast twitch fibers and lower succinate dehydrogenase activity. The latter finding suggests that mitochondrial content of muscle is reduced in heart failure and that impaired aerobic-oxidative capacity may play a role in the limitation of systemic exercise capacity.

Temperature and Abscisic Acid Can Be Used to Regulate Survival, Growth, and Differentiation of Cultured Guard Cell Protoplasts of Tree Tobacco.

Guard cell protoplasts isolated from leaves of Nicotiana glauca (Graham) were cultured. Conditions were sought that would maximize survival and maintain cells in their differentiated state. Temperature was an important determinant of survival, growth, and differentiation. As temperatures were increased from 24 to 32[deg]C, survival for 1 week in culture increased from approximately 20% to approximately 80% of cells used to initiate cultures. At all of these temperatures, approximately 90% of surviving cells divided to form callus tissue. "Footprint" areas of cells cultured for 1 week at 32[deg]C increased almost 30-fold. Cells cultured for 1 week at 34 to 40[deg]C also survived in high percentages (approximately 80%), but they retained a morphology similar to that of guard cells and they did not divide. Footprint areas of cells cultured for 1 week at 38[deg]C increased 6-fold. Cells cultured at 36 to 40[deg]C in media containing 0.1 or 1.0 [mu]M abscisic acid survived in high percentages and did not divide. At 38[deg]C their footprint areas did not increase, but cells so cultured increased in diameter when treated with fusicoccin. Morphologies and electrophoretic profiles of total sodium dodecyl sulfate-extractable proteins suggest that cells cultured at 38[deg]C in media containing abscisic acid remain differentiated. L-[alpha]-(2-Aminoethoxyvinyl)-glycine reduced survival to <1% at 26 or 32[deg]C but had no effect at 38[deg]C. At lower temperatures, cell growth and survival appear to be ethylene dependent.

Exercise intolerance in chronic heart failure is not associated with impaired recovery of muscle function or submaximal exercise performance.

OBJECTIVES: This study investigated whether recovery of skeletal muscle function is impaired in patients with heart failure and whether impaired recovery is associated with abnormal submaximal systemic exercise tolerance during repeated testing. BACKGROUND: Patients with heart failure experience fatigue during daily activities. Because abnormalities of skeletal muscle play a role in their exercise intolerance, these symptoms may reflect a delay in muscle recovery and a resulting limitation in submaximal exercise tolerance. METHODS: Two protocols were used. In protocol 1, knee extensor strength and endurance, and their recovery after fatiguing exercise, were evaluated in 11 patients (mean [+/- SEM] age 62 +/- 5 years, New York Heart Association functional class 2.3 +/- 0.2, ejection fraction 24 +/- 5%) and in 10 age-matched sedentary control subjects. Protocol 2 examined the recovery of knee extensor endurance and submaximal exercise tolerance, as quantified on a self-powered treadmill, over 24 h in 18 patients (mean age 65 +/- 3 years, functional class 2.4 +/- 0.2, ejection fraction 23 +/- 3%) and in 10 control subjects. RESULTS: Peak oxygen consumption was reduced in both heart failure groups (15.4 +/- 1.4 and 15.6 +/- 1.0 ml/kg per min) compared with that in the respective control groups (23.1 +/- 2.9 and 25.6 +/- 1.0 ml/kg per min, both p < 0.05), as was muscle endurance but not muscle strength. In protocol 1, knee extensor endurance recovered more slowly in the patients than in control subjects (to 62 +/- 4% and 87 +/- 7% of the baseline value after 5 min, respectively, p < 0.05). In protocol 2, submaximal exercise tolerance was lower in the patients with heart failure than in control subjects (1,075 +/- 116 vs. 1,390 +/- 110 m), but knee extensor endurance and walking distance recovered fully by 10 and 30 min, respectively. CONCLUSIONS: Although these findings confirm earlier studies that demonstrated impaired muscle endurance in patients with heart failure, the results provide no evidence that recovery of either muscle function or submaximal exercise tolerance is delayed beyond the initial 5 to 10 min after exercise.

AIDS: the epidemic no one wants to touch.

PIP: In February 1990, the All India Institute of Medical Sciences issued a memorandum stating that no patients with acquired immunodeficiency syndrome (AIDS) would be accepted into its hospital until a special AIDS Unit was established. This position was taken in response to fears on the part of medical staff and physicians that they are at risk of contracting the AIDS virus through patient contact. However, such a stance is contrary to scientific evidence that AIDS transmission can be prevented in medical settings if appropriate precautions are taken and ignores the responsibility on the part of government health facilities to provide care to all patients in need. The basis of AIDS prevention in medical facilities is the avoidance of needle sticks in the handling of potentially contaminated, sharp instruments. Among the precautionary guidelines recommended by the objects with household bleach; the wearing of gloves, a gown, mask, and eye protection in all contact with potentially infected bodily fluids; provision of a special container for discarded needles; and the use of sealed bags for soiled linen and reusable supplies. There is no need to isolate patients with the AIDS virus unless they are too sick to maintain personal hygiene or have central nervous system involvement that is producing behavioral disorders.^ieng